How Does One Check Knife (Daf 17)

The Gamara said we should check the sackin b'sira tifer and class b'sira means you check it with your flesh. Tifer, you're checking with your nail. In class there's three sides on the sackin. The sackin then each has two sides of the we don't know how to check the b'sira because if you're going to use your flesh it's going to be cut. So today we're doing the b'dikas a tifer twice one instead of b'sira. So now we're going to show you how we're doing a tifer. We're going with your nails. First we're going on the surface of the sackin with your nail to b'dek once two up. This is one set of the b'dika on the surface. Now we're going to show you a class the other two sides we're checking. You're making the knife a little angle. You're going down. You're going up. Now you you angle the sackin like this. You're going down. You're going up. That b'dikas we're doing twice. So meaning you're doing instead of b'sira you have to do b'sira on three sides. Meaning you have six b'dikas because you have to check it with the b'sira. Then you have an other six b'dikas of the three sides. Two on each side is all together it's 12 b'dikas. There is you learn it from the pussikish tambu za bu za it's like za is 12. So you have a siman that this is the amount of b'dikas you have to check to be the sackin before the sh'chita.