A match-up zone
The top is always responsible for the ball against the initial offensive alignment.
Wings have first pass, posts have next pass.
Bump positions whenever possible to return to a 3-2 alignment.
The on-ball defender does not call "ball" he announces where the ball is going, e.g. "base" (baseline).
See Defences - 12-13 zone, 1-2-2, Pistons 1-2-2 match-up.
When his partner X5 goes out (on the ball), X4 comes across.
Covering the low post can be a philosophical choice, they play behind, and 3/4 when the ball is on top to prevent an easy high-low entry.
A wing covers a skip pass, a post covers the next pass if it goes lower, the top covers if it goes higher.
X2 can bump X1 on a pass to 2, but if the ball goes right to 1, X3 has it, X2 sprints through to the other wing, re-set the triangle.
On a skip pass from the corner, X1 may have to bump X3.
X5 covers for X3.
The high post is covered by the weakside post (but see below).
They do not pressure the high post if he is not a shooter.
Guards don't cover the high post because they are worried about shooters.
They don't deny it, they don't mind if it goes there for a challenged 15-footer.
The weakside wing is in help, but ready to close out on a skip pass.
On a pass to the high post, the weakside wing must drop to cover the rim or weakside corner, the post defenders match up with the high post and low post.
Guards are in gaps, and can dig but not commit especially if they have an "Allen" (are guarding a shooter).
If 4 passes to 1, X4 would go back down (ballside), or X5 would run across.
Game footage shows X5 covering the high post with no other ballside attacker.
Game footage shows X4 ballside with no ballside attacker to cover.
X5 takes a skip pass to 5.
1 pushes 2 to the corner, X2 bumps X1, X5 comes with 5.
Cover ballscreens by switching with the top players (go under the roller, force the dribbler high).
Pistons - X1 pushes X2 down with 2, both stayed matched up (unless 2 cuts through).
X4 goes out on a pass to the corner, X5 comes down to cover 4.
(Variation - X5 comes down to help on the post before the pass, X1 covers the high post)
X1 can cover the high post.
On a pass to 4, try to re-set the 3-2, X5 has it, X4 comes back, X2 has 2, X1 has 1.
Know your close-out constantly, that's the match-up component.