in NFL cut block is legal while chop block is not.
what is the difference between them?

thanks

A chop block occurs when a blocker is engaging an opponent above the waist and his teammate makes a delayed block at or below the knees. It's always illegal.

A "cut" block is a coaching term for blocking below the waist. It can be illegal in certain situations.

Actually, the initial block does not have to be above the waist, it can be below the waist. But, you're right, the second block must be delayed and at or below the knees to be a chop block. Had one last night.

True in HS but in the NFL?

In either case, I've never seen a low-low.

Only in NF must the 2nd block be delayed and at or below the knees. In NF simultaneous blocks are legal. 2-3-9

In NCAA, it can be a high-low, low-high, or low-low combination and in some cases simultaneous blocks in the above mentioned are fouls, and in some cases they are legal blocks. See AR 2-3-3 for situations.

In NFL, a chop block can also be a low-high blocking combination. Also in the NFL it can be a chop block if only one block occurs. This example is "on a forward pass play, A1 chops a defensive player while A2 confronts the defensive player in a pass-blocking posture but has not physically engaged with the defensive player (a "lure"). (12-2-14c) There are 10 such examples given after the chop block definition in 12-2-14.

The Fed did a nice job in this year's case book. They have two tables on page 15 that clearly spells it out. It helped earlier in the year having it handy in my bag when I met with a coach before a game. I showed him the table and it cleared things up in his mind. He thought simultaneous high/low or low/low was illegal.

The table was also in last years POE, and I agree its helpful. I have had players complain that they are being chop blocked, I ask them what the definition of a chop block is and they usually shut up. There seems to be a big misconception that chop block and cut block and synonmous.

Quote: "Also in the NFL it can be a chop block if only one block occurs"

The same thing applies in the NCAA book, sort of. If you are "in the act of disengaging, or have just disengaged, but is still 'confronting' the opponent" (I think that's pretty much the wording), then a block at the thigh or below would be a chop block, even without the blocked player being in contact with the first blocker.