Mechatech and Kore'a: Does Cutting to Size Mean Exact Measurement or Intended Use?

Topics

• Hilchos Shabbos: Mechatech and Kore'a — Cutting to Size, Perforations, and Practical Questions
• Opening the Mishnah Berurah: What Is Mechatech?
• Mechatech Versus Kore'a
• What Does It Mean to Be Makpid on a Measurement?
• Cutting a Tablet in Half
• Paper and Aluminum Foil: By Hand or with a Kli?
• Toothpicks: A Very Important Example
• The Case of a Toothpick: A Size Without a Ruler
• Large Pieces, Small Pieces and a Possible Diyuk
• What Does "Makpid Al Hamiddah" Really Mean?
• Chazarah: The Difference Between Mechatech and Kore'a
• Toilet Paper Where Nothing Else Is Available
• Aluminum Foil and a Choleh
• Opening a Food Package Along the Perforation
• Opening Soda and Tuna Cans
• The Tissue Box and Other Designated Openings
• Rav Shlomo Zalman Auerbach's Raya: A Designated Opening Is Not Necessarily Mechatech
• A Personal Digression About Being Too Frum
• Reading Rav Shlomo Zalman Inside: "I Don't Care If It's Longer or Shorter"
• The Pill That's Cut for Its Dose
• Separating Yogurt Cups and Ice Pops: Are You Making a Particular Size?
• Cutting a Disposable Tablecloth
• Distinguishing Opening from Cutting to Size
• Returning to the Toothpick
• The Two Basic Ways to Understand Mechatech
• A Functional Measure Without a Ruler
• Kore'a, Mechatech, and Mesaken Kli Are Different Questions
• The Food Question

Transcript

# Hilchos Shabbos: Mechatech and Kore'a — Cutting to Size, Perforations, and Practical Questions

## Opening the Mishnah Berurah: What Is Mechatech?

Rabosai, we're returning to the **Mishnah Berurah, Orach Chaim 322:18**. Yesterday we were learning about *chituch* and *ketimah*, and how the din changes when someone intends to cut something to a particular size.

We're going to continue the sugya of **melachas Mechatech**, one of the thirty-nine melachos of Shabbos.

Before we begin, a student raises a practical question about somebody who inadvertently damaged another person's car. He wants to know whether he must go tell the owner about a tiny scratch which the owner would probably never notice.

I have discussed such questions with people, including matters that **Rav Yechezkel Roth** reportedly spoke about, and another person whose name was mentioned in the discussion. But I want you to understand that the halachah of **damages, disclosure, safety and restitution** is a separate sugya.

There may be legitimate questions about the owner's awareness of damage, the amount of actual loss and personal safety, but no one should take these fragmented classroom comments as a practical permission to conceal property damage or evade responsibility. That needs a real shailah with all the facts.

All right, let's return to the Mishnah Berurah.

## Mechatech Versus Kore'a

The first distinction is simple to state but more difficult to define.

**Kore'a** is tearing. In certain contexts one tears without being particularly concerned with an exact measurement or size.

**Mechatech** is cutting **lefi hamiddah**—according to a measurement.

But what does **lefi hamiddah** mean?

Does it mean sitting there with a ruler and saying, "I need a piece exactly six inches long, no more and no less"?

Or can it also mean that I want a piece of a **particular useful size**, even though I never measured it in inches?

That is the entire question.

Look closely at the words in **Mishnah Berurah 322:18** describing the melachah. He says that the person cutting something is **makpid on its measurement**, the length and width, and cuts with **kavanah**.

I want you to underline the important expressions:

**"מקפיד על מדתו"**—he is particular about its size.

**"אורך ורוחב"**—length and width.

**"חותך בכוונה"**—he cuts intentionally.

And in contrast, we have the expression **"דרך הפסד"**, a destructive act, and **"כמתעסק"**, an act without the same purposeful intention.

Now consider this. Why does the Mishnah Berurah contrast cutting with **specific intention** against an action without that intention?

Couldn't a person cut **intentionally**, yet not be particular about the **measurement**?

For example, I want a small piece of paper, and I cut one off. I'm certainly not doing it accidentally. But I don't care whether it's four inches, five inches, or six.

Is that called **Mechatech**?

That's a tremendous question.

And it will be the key to understanding the difference between **Rav Shlomo Zalman Auerbach** and some other great poskim in their discussions about cutting along **perforated lines** on Shabbos.

## What Does It Mean to Be Makpid on a Measurement?

Now, rabosai, open the Mishnah Berurah again. I want you to be medayek in every expression.

He says *Mechatech* applies to **any material** where the person cuts it carefully to an intended size. Not only leather. Wood, metal and other materials can be involved, depending on how the work is done.

And this is different from ordinary tearing without an intended measurement.

But there are several important points.

First, **the measurement**. The expression **"makpid al midasai"** is the key. Does this mean **a precise length or width**, or can it mean **a size suited to the intended purpose**?

Second, **intention**. He discusses *kavanah*—the person is cutting for that useful size.

Third, the ordinary method of cutting. Does the object ordinarily get cut with a **kli**, an instrument, or by **yad**, by hand? That too can change whether the act is considered the normal manner of performing the melachah, and whether we are discussing de'oraisa or a lesser level of prohibition.

And fourth, what are we cutting? Do the rules of *Mechatech* apply in the same way to **ochlin**, edible food, as to other materials?

Let's take them one by one.

### Cutting a Tablet in Half

A talmid asks about a **pill**, a tablet of medication.

Suppose the doctor has prescribed half a tablet. The whole tablet is one size, and you take a knife or tablet cutter to split it.

Have you committed **Mechatech** by cutting it to a particular size?

A person says, "But I need half the tablet!"

Yes, but **why** do you need half?

Do you need a tablet of a particular **length and shape**? Or do you need **half the dose**?

That may be a tremendous distinction.

Some Acharonim discuss whether medications can be compared with **ochlin** for this melachah. We cannot simply assume that because a pill is swallowed it has exactly the same halachic status as a vegetable or other food.

And not every tablet is medically safe to divide. **Extended-release, coated or otherwise specially formulated tablets** can be dangerous to split without verifying the prescription. We are discussing the halachic category, not advising anyone to alter a dose.

But as a *chakirah*, the question is good: if I cut a tablet because I need a certain **quantity**, is that equivalent to cutting an object for a precise **dimension**?

I want to see how **Rav Shlomo Zalman Auerbach** understands that difference.

### Paper and Aluminum Foil: By Hand or with a Kli?

Now let's take **paper**.

A piece of paper can be cut with scissors, and it can also be torn by hand. Depending on what a person intends, the method could be normal.

How about **aluminum foil**?

Sometimes it is torn by hand against the serrated metal edge of the box. Is that called cutting *b'kli*, or does the foil's ordinary use change how we describe the act?

We need to know what qualifies as **derech melachah**, the normal way of doing it.

The Mishnah Berurah's discussion of cutting with **hand or instrument** distinguishes the higher Torah-level category from some rabbinically prohibited ways of doing the same sort of act.

But that doesn't give permission merely because a person chose an unusual instrument. We still need to account for **Kore'a**, for making an object useful, and for all the related melachos.

### Toothpicks: A Very Important Example

Now the students raise the example of making a **toothpick**.

The Shulchan Aruch in **Orach Chaim 322:4–5** discusses *ketimah*, breaking or shaping materials such as a small stick for various uses, including the special issues of making a toothpick.

And the **Rambam, Hilchos Shabbos 11:7**, discusses cutting or shaping an object to a desired measure.

But tell me: when somebody makes a toothpick, does he sit with a ruler and insist on a piece exactly two inches and one-sixteenth long?

No!

He simply wants a piece **small and narrow enough to fit between his teeth** and sufficiently long to hold.

So if the case is called **Mechatech**, doesn't that show that **lefi hamiddah** can mean a useful, intended shape rather than a measurement taken with a ruler?

That is a strong kashya on a narrow understanding of the word *middah*.

On the other hand, maybe the toothpick case involves a different type of shaping, and the source can't automatically be applied to every case of perforation or tearing.

We have to read the Rambam and the Mishnah Berurah carefully.

I want you to see why the word **middah** is doing so much work in this sugya.

## The Case of a Toothpick: A Size Without a Ruler

Now let's look more carefully at **making a toothpick**.

I was asked a good kashya, and I want the olam to hear it.

The Rambam discusses **Mechatech** in a case where somebody shapes a piece of wood or other material according to an intended use. The Mishnah Berurah also brings the toothpick case in connection with **kitum**, shaping a small stick.

What is the *middah* in a toothpick?

Surely no one is measuring the exact number of inches. He wants a piece **slender enough to go between the teeth**, with enough length to hold it.

If he made it a bit longer, that would be fine. If he made it a little shorter, it might also be fine, provided it still serves its purpose.

So does that count as **makpid al hamiddah**?

I am suggesting that *middah* may mean more than numerical precision. It may mean **the intended size or shape required for the object's use**.

A tablecloth is another example. Suppose I want to cut a cover to fit a particular table. I don't have to sit there measuring to the millimeter. I know roughly how big my table is, and I want the cloth to be big enough to cover it.

If I cut a piece specifically for that table, perhaps I'm being **makpid** on its useful size, even without a ruler.

Some of the poskim understand Mechatech broadly in that direction.

But now ask the opposite question. What if I take a paper towel and simply tear off **some** paper? I don't care how long or short it is. Would that be the same thing?

Maybe not.

This is the great machlokes we are heading toward.

### Large Pieces, Small Pieces and a Possible Diyuk

The students raise a distinction in the Mishnah Berurah concerning cutting a **larger or smaller piece**. Perhaps when somebody deliberately makes a piece suited for use, the required measurement need only be approximate. Or perhaps the case of making something very small has its own way of defining the melachah.

I want to be medayek in the wording, but I am not certain the raya is as clear as I first thought.

Somebody points to a passage in **Mishnah Berurah 321:45** concerning preparing pepper or other foods, and argues that the word **middah** there suggests a different distinction.

I hear it. Let's read the whole text. You can't just take one phrase and declare a raya for your own sevara.

There are Acharonim, including **Rav Simcha Bunim Cohen**, whose discussion of the thirty-nine melachos does not necessarily support my proposed distinction.

I know that! It's fine. A good kashya is part of learning. The whole point is to see what the Rishonim and Acharonim actually say.

### What Does "Makpid Al Hamiddah" Really Mean?

There are two possible ways to understand the condition.

First: **exact measured size**. Mechatech happens when the person is concerned with a specific dimension. If he cuts a little longer or shorter and doesn't care, perhaps the requirement is absent.

Second: **functional size**. A person may be particular because he needs a useful object of a certain approximate form. He might not care whether it is exactly four inches, but he does care that it is long enough, short enough or narrow enough for a purpose.

These are different ways to understand *lefi hamiddah*.

And each way may produce different results in cases involving **toothpicks, paper, foil, packaging and perforated lines**.

This is why I want us to slow down rather than run ahead to a practical ruling.

Rabosai, now that we've raised the questions, let's make a chazarah and examine them in order.

## Chazarah: The Difference Between Mechatech and Kore'a

All right, rabosai, I realize I've said a great deal in a short time. Let's go back and learn it properly.

What is the distinction between **Mechatech** and **Kore'a**?

**Mechatech** involves cutting **lefi hamiddah**, according to a desired measure.

**Kore'a** is tearing, and it can be present even where a person is not particular about cutting an item to a useful dimension.

But be careful. That does not mean that every tear without measurement is automatically permitted on Shabbos. The melachah of Kore'a, the rabbinic prohibitions associated with tearing, and the act of making an object usable must each be analyzed separately.

Now I want to bring out a practical nafka minah.

### Toilet Paper Where Nothing Else Is Available

Suppose someone is in the bathroom on Shabbos and has no prepared toilet paper or tissues.

There is a recognized discussion of **kavod habriyos**, human dignity, and limited leniencies for certain rabbinically prohibited actions when there is genuine need and no suitable alternative.

The relevant sources include **Shulchan Aruch OC 312:1**, the laws of **Kore'a** in OC 340, and the detailed discussion in **Shemiras Shabbos Kehilchasah**, chapter 23.

But suppose one has a roll with **perforated lines**.

If tearing off the paper itself requires a **shinui** in the exceptional circumstances under discussion, should the person specifically **avoid tearing on the perforation** so that he doesn't also do **Mechatech**?

One opinion says: yes. Tearing on a prepared line means you're choosing the exact intended point, and that may be an additional problem of cutting to size.

The other approach says: **maybe not**. Perhaps the person doesn't care about the size at all. He tears at the perforation merely because **that is where it's easiest to tear**.

And this is where the positions attributed to **Rav Shlomo Zalman Auerbach** and **Rav Yosef Shalom Elyashiv** become so important.

According to Rav Shlomo Zalman's reasoning as reported here, the very fact that the paper happens to be perforated does not prove the person wants a specific size. If he would be equally satisfied with a piece an inch longer or shorter, his intention isn't to cut *lefi hamiddah*.

According to the more stringent approach quoted in the name of Rav Elyashiv, choosing a designated cutting line may itself be the kind of purposeful cutting relevant to Mechatech.

This is a significant disagreement about **the definition of the melachah**, not just a technical question about paper.

But **neither view gives general permission to tear toilet paper at will on Shabbos**. The underlying issues of Kore'a and preparing an object for use remain. The limited case of necessity and kavod habriyos must not be generalized.

### Aluminum Foil and a Choleh

Now suppose we have a **choleh**, and someone needs to cover a plate of food or a container with aluminum foil.

How would you analyze the case?

First, does the foil ordinarily get torn by **hand** or by means of a cutting edge?

Second, is the person trying to produce a piece of a particular **size** to fit a plate or pot?

Third, if a non-Jew is asked to help, the laws of **amirah le'akum** and the nature of the underlying prohibition enter the discussion.

A talmid suggests tearing the foil with an unusual method so the act might be only rabbinic, and then relying on a further allowance for the needs of a choleh.

Fine, that's a possible *cheshbon*—but we have to study which levels of illness and which activities allow which forms of assistance. We cannot simply say every act becomes permissible because food is involved.

For our sugya, the main question remains: **if I want the foil to cover the pot, am I cutting to a useful measure even without measuring an exact length?**

That depends on which understanding of *lefi hamiddah* we adopt.

And now let's apply the same idea to **opening food packaging**.

## Opening a Food Package Along the Perforation

Take a package of **cheese**. There are packages with a perforated line or a designated place where a person is supposed to open them.

When I tear at that line, am I doing **Mechatech**?

Someone says: "Of course you are. You're cutting at an exact place!"

But another person says: "Why am I cutting there? Not because I need a container of some precise measurement. I'm cutting there because the manufacturer made it **easy to open** at that point."

Do you hear the difference?

If I need a piece of wood to be **six inches long**, the measurement is part of what I want.

If I want to **open a package**, perhaps I don't care whether the tear is a little higher or lower. I want access to the food.

So why should the mere existence of a perforated line make the act Mechatech?

On the other hand, what if I'm making a **new usable opening**, or separating the package so that a particular portion remains in a precise shape? Perhaps the intended location does matter.

And maybe an opening performed **derech hefsed**, destructively, is different from an opening intended to construct a new useful container.

We must distinguish **Mechatech**, **Kore'a**, and **mesaken kli**. All three can become relevant in different forms of food packaging.

### Opening Soda and Tuna Cans

And that leads to an entirely different sugya: **opening cans on Shabbos**.

Someone asks about a soda can. Someone else brings up a tuna can.

A person may intend to use the can only long enough to take out the contents, and then throw it away. Does that mean he is not creating a lasting *kli*?

I grew up seeing people open cans and discard them as ordinary practice. In some communities, later Acharonim have been stringent about certain methods of opening cans. We have to learn the underlying arguments.

And you know me—I'll joke with the olam. A fellow tells me he's careful not to open tuna cans on Shabbos. I say, "Wonderful! You'll go straight to Olam Haba and sit with the greatest tzaddikim!"

I'm joking. The point is that **different legitimate practices and halachic analyses exist**, and we have to understand them rather than laugh at people for being careful.

I speak with tremendous love about some of the poskim whose views differ from what I grew up with. Sometimes I'll say they are responsible for a particular chumrah and laugh, but I respect their Torah deeply.

The real issue is whether the act of opening is **destructive**, whether it creates a **usable vessel**, and what kind of **cut or opening** is being made.

You cannot simply say, "It's a disposable can, so it must be mutar." Nor can you decide every modern package by treating all openings identically.

### The Tissue Box and Other Designated Openings

What about a **tissue box**? There is often an oval perforated piece that one removes from the top.

Is removing it **Mechatech** because you're cutting along a designated line? Or is it opening the box, and the exact size of the piece is not the person's intention?

And what about a plastic package which is already sealed in a special way, with a designated place to tear?

Again, the same question.

One view emphasizes **the predetermined cut**, even where the person has no measurement in mind.

The other view emphasizes **the person's purpose**: whether he actually wants the resulting piece or opening in a particular shape or size.

It's a beautiful sugya. But don't misunderstand me: even if one opinion removes the specific problem of **Mechatech**, the activity may still involve **Kore'a** or **tikkun kli**.

And then someone asks about a bag that will be resealed. That may be more complicated again, because the person may be preserving a useful container.

So, rabosai, let's go back. I want to show you the source **inside**, not just give examples all night long.

The question is the distinction between a person who cuts **lefi hamiddah** and one who merely cuts in the **most convenient place**.

## Rav Shlomo Zalman Auerbach's Raya: A Designated Opening Is Not Necessarily Mechatech

Now let's look at **Rav Shlomo Zalman Auerbach's** reasoning.

The speaker cites a discussion about **"הפותח בית הצואר בשבת"**—opening the neck hole of a garment on Shabbos—which the Gemara discusses in connection with making a garment usable.

Rav Shlomo Zalman asks: if a person opens something at a designated place, why is the Gemara's discussion not simply framed as **Mechatech**?

The suggested answer is that the person may be concerned with **opening** the garment, not cutting it to a measurement.

Do you hear how important that distinction is?

A person may act at a **specific location** without intending to produce a piece of a **specific size**.

That is an extremely important insight for the sugya of perforated toilet paper, food packages and similar examples.

But it doesn't make opening a garment or package permitted. The very source about opening a neckline raises **its own Shabbos problems**, including making an article fit for use. The raya is about the **definition of Mechatech**, not a blanket practical heter.

The olam keeps interrupting me with applications. Toilet paper, tissues, kitchen foil, paper towels—you want to decide everything at once!

I understand. But first we have to read the source.

I say, **"Take out Shemiras Shabbos Kehilchasah, perek chaf-gimmel."**

The exact note is cited differently in different editions. In the source as I remember it, a note from Rav Shlomo Zalman explains that if the person doesn't care whether the paper is a little longer or shorter, **the act is not Mechatech for the sake of a measurement**.

The passage we later read aloud says, in substance:

**"דכיון שהחותך אינו מקפיד אם היה עושה זה יותר ארוך או יותר קצר ... אין זה שייך כלל למלאכת מחתך."**

Since the person cutting is not particular whether he would make it longer or shorter, the act does not come under Mechatech.

That is the heart of his reasoning.

But the particular circumstances and the related questions of **Kore'a** must still be respected.

### A Personal Digression About Being Too Frum

Somebody starts asking whether I really follow every possible chumrah.

And I want to tell you something. Before I came to **Lakewood**, I was so particular about certain shitos that at one point I would wear **four or five pairs of tzitzis**, trying to satisfy different opinions.

My wife told me, **"You have to stop all of this!"**

She said that if I walked around like that, people would think I was completely out of touch!

I tell you the story with a smile. You have to know what is a serious halachic requirement, what is a chumrah and how to live like a normal person.

I remember **Rav Shimon** visiting our family in Queens before Pesach. There was a large kabbolas ponim, and the children were asking about his tzitzis and the different ways he wore them.

A rebbetzin answered with great humor that she had been asking him about those tzitzis for years herself.

The details of the names and exact shitos in this side conversation are fragmented in the original transcription, so I am not assigning a definite halachic position to the anecdote.

But it's part of the atmosphere of the shiur—serious learning mixed with humor, respect for different gedolim and the recognition that a person needs **good judgment**.

I also remember being a bachur and visiting a gadol in a basement apartment before Pesach. In those days you could sometimes sit and speak to him for hours. It was so accessible and so precious. I remember him walking around in slippers, pajamas and his tzitzis, and I remember how much I learned simply by being able to talk with him.

I treasure those encounters.

All right, rabosai, let's come back to the Mishnah Berurah and read **the actual words of Rav Shlomo Zalman**. Then we'll take the applications one at a time.

## Reading Rav Shlomo Zalman Inside: "I Don't Care If It's Longer or Shorter"

All right, rabosai, we have the sefer open.

Look at **Shemiras Shabbos Kehilchasah, chapter 23**, in the note quoting **Rav Shlomo Zalman Auerbach**. The footnote number may be different in different editions.

His words are quoted in the shiur as:

**"דכיון שהחותך אינו מקפיד אם היה עושה זה יותר ארוך או יותר קצר, והוא רק חותך במקום הנוח לו, אין זה שייך כלל למלאכת מחתך."**

Since the person cutting is not particular whether he would make it longer or shorter, and is only cutting **at the most convenient place**, the act has no connection with the melachah of Mechatech.

That's the whole yesod.

**Mechatech is not merely "cutting at a line." It is cutting for a size.**

If the person doesn't care about the length or width, why should the manufacturer's perforation transform his action into Mechatech?

It was already prepared there. It is easier to tear. Had they put the perforation elsewhere, he would have used it there instead.

That is the reasoning of Rav Shlomo Zalman.

But I heard a shiur from **Rav Yisrael**, in which he described a different approach of his father, **Rav Yosef Shalom Elyashiv**, to tearing on the designated line.

The name and parent-child identification are clear from the oral discussion, but the exact printed source for that contrasting ruling should be located.

According to the more stringent approach, cutting at the specifically designed place may be regarded as a purposeful act of **Mechatech**, even if the person isn't measuring it in inches.

So we're dealing with a genuine **machlokes in defining lefi hamiddah**.

Now let's test that distinction against a few cases.

### The Pill That's Cut for Its Dose

Remember the tablet we discussed earlier.

A person must take **half a prescribed tablet**, if the tablet is one the doctor or pharmacist says may be divided.

Why does he cut it?

Not because he needs a pill with a particular **length or width**. He needs **half the total amount** of medicine.

If it were divided into four quarters and he took two of those pieces, the dosage could be equivalent, assuming that particular product can safely be split in that manner.

That is a possible example of the distinction between **an amount** and **the dimensions of the resulting object**.

The shiur quotes **Shemiras Shabbos Kehilchasah, chapter 33**, as discussing the halachic rules of dividing medication on Shabbos.

But different medications and levels of medical need bring other Shabbos and clinical issues. Don't take this *Mechatech* analysis as permission to split any pill in practice.

I want the lomdus.

A person wants a **four-by-four tablecloth** to fit a particular table. That is a functional size. The resulting dimensions are what matter to his use.

A person wants **half a dose** of medicine. Perhaps the resulting dimensions do not matter; only the quantity matters.

Do you see how the term *middah* might be understood differently?

Now let's bring in another common case: several **yogurt containers** joined together by perforated plastic.

Does the person want a **particular size**, or is he simply separating one complete container from the others?

## Separating Yogurt Cups and Ice Pops: Are You Making a Particular Size?

Now imagine you buy a package of **six yogurts**, attached to each other. Often they are connected by narrow strips of plastic, perhaps marked or perforated, so that you can separate one container from the others.

You want to take **one yogurt** and give it to your child.

Are you cutting **lefi hamiddah**?

On one hand, you are separating a very particular unit. You want one whole container, not half a container or a random piece of plastic.

On the other hand, you are not measuring the **size** of the plastic at all. You merely want to separate a container that was already formed.

Now, the shiur cites a stringent teshuvah from **Rav Shmuel Wosner**, author of **Shevet HaLevi**, concerning the separation of such joined products.

What is the concern? He may consider the separation at the designated line an act of Mechatech. But we need to examine the full teshuvah and the precise product. The source and circumstances are not fully established from the oral transcript.

Some later summaries of the Acharonim distinguish between **separating complete individual packages** and **opening a sealed container**, and other melachos may arise.

So we cannot say, "Yogurt cups mutar," or "Yogurt cups asur," merely because we have a perforation.

The facts matter.

Someone brings up the connected **ice pops**, the kind sold in a strip where you tear off one packet.

Perhaps separating the packets is comparable to separating individual yogurt containers. But perhaps **Kore'a**, cutting letters, or making a particular package usable introduces additional questions.

And don't forget whether you are creating a useful portion or merely tearing the connection between already finished items.

It's a very good sugya.

### Cutting a Disposable Tablecloth

What if you have a roll of **disposable tablecloth material** and want to cut a piece to cover your table?

Now the issue may be quite different.

You know the size of your table. You need the cloth to reach the proper length. Even if you haven't taken out a measuring tape, you are particular that the resulting cloth be **large enough to serve as a table covering**.

So perhaps that is genuinely cutting **lefi hamiddah**.

A student says, "But I don't care if it hangs down another two inches!"

True. But maybe that's still a functional measurement. You want a piece that fits your purpose.

If Rav Shlomo Zalman's position requires not caring about the piece's useful size, this case might not be included even according to his lenient analysis of toilet-paper perforations.

That is why you must not take his words out of context.

### Distinguishing Opening from Cutting to Size

Suppose you tear open a **bag of food**.

You are destroying the seal to take out the contents. You don't care if the opening is half an inch higher or lower, so long as you can get the food out.

That may be different from cutting off a piece of foil or tablecloth in order to obtain a usable object of a certain length.

But then we have the other questions: **Kore'a**, **mesaken kli**, destructive tearing, and whether the bag is being preserved as a usable container.

And what about an **ice pop**? You might be opening it just to eat the contents immediately and throw away the wrapper. Does that fall under the limited allowances for preparing food?

Some poskim distinguish these cases. But the simple claim that "all food wrappers are mutar because they're disposable" is not correct.

We're learning the definition of **Mechatech** first. Then we need to apply the other halachos.

## Returning to the Toothpick

Someone brings us back to the **toothpick**.

It's a particularly powerful example because the intended use requires **a certain kind of shape**, even without an exact numerical measurement.

If you need a stick narrow enough to go between the teeth, that is a **functional specification**.

So does that prove the broader understanding of *lefi hamiddah*?

Perhaps. But the toothpick can also involve **makkeh b'patish**, **mesaken kli**, and special source distinctions about materials fit for animal food.

It's not enough to identify one word and disregard the rest of the halachah.

What I want the olam to appreciate is the range of possibilities. A practical act can have a specific location but no intended size, or a functional desired size without a measured number of inches.

The definition of *Mechatech* is where the whole analysis begins.

## The Two Basic Ways to Understand Mechatech

Rabosai, I want to gather all the examples together.

We began with one question: **what does "lefi hamiddah" mean?**

According to one analysis, the condition is that a person cuts to **a specific desired measurement or functional size**. He needs a piece for a particular use, and it must be of a certain size or shape for that purpose.

According to another analysis, the word *middah* has a narrower meaning. If the person doesn't really care whether the resulting piece is a bit longer or shorter, then perhaps he isn't particular about a measurement, even though he deliberately chooses the most convenient cutting place.

The debate over **perforated toilet paper** is a test case. Under circumstances of genuine **kavod habriyos**, there may be a limited allowance to tear using a shinui if no suitable prepared material is available. One view says a person should **avoid the perforated line** to avoid an added Mechatech issue. Rav Shlomo Zalman Auerbach's reasoning suggests that the line doesn't by itself constitute Mechatech if the size is irrelevant to the person.

But both approaches have to account for **Kore'a**. Don't forget it.

That's why, in ordinary circumstances, you **prepare toilet paper and tissues before Shabbos**. Nobody should walk away imagining that our *chakirah* gives a general heter to tear from a roll.

### A Functional Measure Without a Ruler

Now the **tablecloth** may come out differently.

If I have a table and want to cut a piece of plastic covering to fit that table, I care about how large the result is. Maybe not to an exact inch, but it needs to cover the table.

So that may be *lefi hamiddah*.

A **toothpick** also may be shaped for a specific function. There is a clear reason it must be sufficiently narrow and sufficiently long.

But when I tear a paper towel just to wipe something, I may be satisfied with almost any useful piece. Perhaps that is why the Acharonim differ about whether the prepared perforation changes the definition of the act.

We can also discuss **opening a soda can**, **tuna can**, **chip bag** or **ice-pop wrapper**, but every one of those may involve different rules.

The halachah isn't based simply on whether the package has a dotted line. It depends on what kind of act is done, what is being created, whether the item will continue to function as a container, and which melachos apply.

### Kore'a, Mechatech, and Mesaken Kli Are Different Questions

Here is a mistake I want you to avoid.

A person learns that something isn't **Mechatech**, so he concludes it must be **mutar**.

No! Who said that?

It could still be **Kore'a**. It could be **mesaken kli**. There may be another prohibition.

A fellow says, "But I tore it destructively!"

That may matter. But what if by tearing it, you create a neat opening or a usable container? Then perhaps it isn't entirely destructive in the halachic sense.

And don't assume that using something only once automatically removes every din of *kli*.

The students raise examples of cans which are thrown away and cans which people eat or drink from. Perhaps those differences matter in some poskim's analysis. But we must learn those sugyos inside before issuing a practical ruling.

### The Food Question

There are also allowances and limitations concerning **food preparation for Shabbos**, and the speaker discusses opening bags to gain access to the food.

The Torah's concern for **oneg Shabbos** and human needs can be relevant to rabbinic restrictions in specified cases.

But a person cannot say that because there is a mitzvah to eat, **all cutting and tearing** becomes permissible.

So don't learn **one heter** and apply it to everything.

I want the olam to remember the main distinction we learned today:

**Mechatech** means cutting to a desired measure or shape.

But **how exact** must the person's desired size be? And is cutting at a perforation without caring about size included?

That is a serious machlokes and an important *lomdishe* question.

It's worth learning slowly.

We have gone through paper, foil, toothpicks, tablecloths, pills, yogurt containers, ice pops, food bags, soda cans and tuna cans. The details differ, but the same foundational question keeps coming back.

And there is no benefit to pretending that all the poskim agree. We need to be honest about the different shitos.

Rabosai, I know we've covered a lot today. This sugya is much bigger than one short summary. We have raised practical applications which demand their own source-by-source learning.

[The recording's substantive transcription ends here during an extended question-and-answer discussion about packaging and food access. No clearly delivered final practical psak covers every case. The final stored chunk is empty. Do not infer unrestricted permission to cut along perforations, tear toilet paper, divide medication, open cans or separate attached food packages.]