Rabbi Aryeh Lebowitz

Now, it's a little bit trite to say that I have a great chidish that a kezias is the size of an olive, because it's really not that simple.

There is a lot of discussion about how big an olive is, and it makes it onto the page of Shulchan Aruch, whether it's a shlish beitzah or a chazi beitzah,

And it's not as straightforward as one might think.

But what you do have, a lot of people do sometimes, is they have these gigantic shiurim of how much matzah they need to eat for a gazayis.

And they assume that they need to swallow it all within, they need to eat it all within two minutes.

Because that's a kedei achilos pras.

Whether or not you need to actually eat it within a given time of kedei achilos pras,

It certainly needs to be in with the Kedai Achilas Pras.

How to define Kedai Achilas Pras is a major Machalokos Abosken.

Min Chaschina holds that Kedai Achilas Pras is defined by each food.

So if a Pras equals six Kezaisen, and you need to eat one Kezais in the amount of time that it takes to eat a Pras of food, that a normal person would take to eat a Pras of that food, that means that if you hold a Kezais, let's say some gigantic shir, let's say you hold a Kezais that's three quarters of a hand Shmur HaMatzah,

then you have the amount of time, let's work with numbers that I could do the math easier on.

Let's say Yuval de Gazayas is a half of a hand shmura matzah, you have the amount of time that it would take a normal person to eat, eating normally,

In addition to that, it's not so posh at all that there's such a giant shir for a Kezias.

Rav Shachar, when we asked him how big a kazayis is, he said roughly like this big.

He made it size like three by three inches or so.

It's the size of a kazayis if you have that much matzah.

They say the stapler used to measure a kazayis by the palm of his hand.

The size of the palm of his hand was what he considered to be a kazayis.

Rav Shachar said that his father-in-law spent time by the seder of Rav Shimon Shkup.