Triangle and 2
A combination defence used against teams that have two main scorers, excellent against great wing players, or a wing and a point guard (here 2 and 1).
X1 and X2 defend scorers 1 and 2 man-to-man, while X3-X4-X5 play a triangle zone. X1 and X2 deny passes to their checks, the point of the triangle helps defend penetration if a scorer gets the ball, and double-teams in scoring range.
Canada Basketball - man-to-man defenders deny all passes to their checks, fight through screens, block out after every shot, and should not follow normal help rules since their job is to keep their checks out of the offence. Some coaches may assign the weakest defenders to these roles since they always have help and aren't required to help. Zone defenders help on scorers, and cover other attackers, who get the ball in scoring range.
coachesclipboard.ca - X3 is the best athlete, covers elbow to elbow, does not go outside the arc, X4 and X5 cover baseline to wing. Complete denial of the two scorers, make them backcut to the help. When a scorer catches the ball, trap with the point of the triangle.
coachesclipboard.net - best, quickest, hardest-working defender X3 covers the foul-line area and above, X4 and X5 play on the low blocks and have corner responsibilities too.
Tab Baldwin (FIBA Assist issue 10) - X1 and X2 defend with full denial, or more passive help-oriented defence. X3 plays mid-post to high post on both sides (not beyond the arc), switches all ballscreens in his area, and helps on dribble penetration by 1 or 2. X4 and X5 play mid-post extended to the baseline on the perimeter.
Julio Lamas (FIBA Assist issue 13) - X1 and X2 play face-to-face, never help on dribble penetration, but do help a helper.
bbhighway.com - you might be just as effective playing good man defence and completely denying the two scorers. If you play triangle and 2, defend the two main players, the hot shooter and probably the point guard, taking the player that organizes the offence out of the game. A team with a two-guard system wouldn't be nearly as much affected.
X3 takes the ball on a pass to the wing.
A pass to an attacker below the foul line can be a problem unless X3 and X4 talk about who goes out to the ball (not both, and not neither).
Winning Hoops - where the opposing point guard is defended man-to-man, the top of the triangle closes out on a pass to the wing and X5 covers the high-post area. X3 stays in to help with penetration and the high post until the ball is passed to the wing.
Tom Billeter (coachingbetterbball.blogspot.com) - the idea is for X1 to force the ball out of point guard 1's hands then deny a pass back. If you don't have a great 1-on-1 perimeter defender, put the worst help defender on 1, he is always making contact, denying passes, and never playing help defence. Second man defender X2 plays regular man defence and gives help.
X3 has ball on the wing, X4 covers the low post, X5 has weakside.
Baldwin - X3 has ball, playing "area" defence, not allowing non-shooter 3 to penetrate or get a good shot, but not consistently pressuring the ball. X4 fronts the low post, X5 zones the midline, defending the weakside post and offering backside help to X4.
coachesclipboard.ca - trap with the top player if the ball goes into the post.
bbhighway.com - the most common way to play against a triangle and 2 is to have a ballside low post and run the third non-scorer to the ballside corner, this can cause the bottom of the triangle to step out, opening up the post for an easy shot. If the player in the corner gets hot, the triangle and 2 is almost immediately neutralized.
Lamas - if the ball is passed to 5, X4 guards him one-on-one without giving him baseline, X5 helps only if 5 goes to the basket, then X2 rotates down. Zone defenders must anticipate a pass to the low post when the ball is below the foul-line extended.
Winning Hoops - you can send X4 out to defend the corner and X5 covers 5, or decide not to go out if 4 is not a three-point shooter or it's out of the opponent's offensive scheme.
Billeter - post defenders always play behind the post.
The triangle rotates on a pass to the corner, X4 takes ball, X5 covers the low post, X3 drops towards the baseline in the middle and has weakside coverage (a deep slide, see Lute Olson 1-1-3).
Variation - X3 covers the low post (a short slide), X5 stays, see Defence - 1-2-2 slider traps.
coachesclipboard.net - X3 covers the ballside low block when the ball goes into the corner.
Lamas - X4 runs to cover 4, X5 guards the low post on the ballside, X3 slides toward the baseline in the middle of the lane.
Canada Basketball - some coaches prefer to have the player guarding the low post play on the bottom side when the ball is in the corner, this can be effective but allows the low post to seal the defender when the ball is reversed.
Options (coachingbball.proboards.com) - use 3-2 or 1-2-2 point zone rotations for the triangle, just take the elbow defenders out, they play man-to-man. Similarly, take the top defender out of a 1-3-1 (he plays man), use 1-3-1 rotations for the zone (for a diamond and 1). For a tandem and 3, the middle and baseline players use 1-3-1 rules, the point and wing players match up and play man-to-man.
Canada Basketball - in a diamond and 1, the bottom player can cover the corners as in a 1-3-1, or keep him in the key area and cover the corners with the wingers.
The triangle is flatter when the ball is near the baseline.
Baldwin - X4 plays area defence, "soft" on the ball, making the pass to 5 difficult. X5 comes across to play behind low post 5 when X4 is extended. X3 plays weakside below the foul line, and takes a pass out of the corner to the top or wings. X4 would hedge down on a pass to 5 but not double team.
Wikipedia - the biggest weakness of the triangle and 2 is its vulnerability to cutters through the lane, and also good passing from the forward spots.
coachesclipboard.ca - when a scorer is coming off a screen his defender trails, the triangle extends, bumps the curl, and watches for the screener slipping or second cutting to the perimeter. The triangle can help on a curl but not on a fade. Trap a ballscreen, or string it (over/under).
Lamas - if 1 or 2 gets an off-ball screen, the screened defender channels the cutter into the middle to get help. On a wing ballscreen, push the ballhandler toward the baseline except if the screen occurs between both scorers, then switch.
Baldwin - on a high or corner ballscreen for a scorer, X3 switches to the scorer coming off the screen, the scorer's defender takes X3's place in the triangle.
Billeter - it will be critical for X1 to be good at tag and trail as the offence will try to run 1 through double and triple screens. Switch ballscreens.
Option - X1 and X2 can switch if 1 and 2 screen for each other, but otherwise do not switch on screens.
Here scorer 1 has the ball in the corner, and is double teamed by X1 and X4 (the point of the triangle).
Here scorer 2 is double-teamed in scoring range by X2 and X3.
Rick Majerus - X2 is two passes from the ball, he doesn't hug 2, he gets off him in a pistols position. On a pass to 3, X3 takes ball, X5 butt fronts or face fronts 5, 4 is not a concern.
On a wing-to-wing skip pass, X3 can't cover the distance in time, X5 comes out top to defend 4, and X3 moves to the middle. The triangle rotates one position counter-clockwise (and would rotate back to where it started on a return skip pass).
Option - X5 stunts at the ball, X3 bumps him back, the triangle does not rotate.
Billeter - on a skip pass, only use short closeouts.
Canada Basketball - an effective strategy against zone defence is to overload one side then reverse the ball. With a help-and-recover technique, initially 4 is guarded by X5 and X4 covers the low post, when the defender who should be covering the ball recovers, X5 drops back to cover the low post and X4 moves back to cover the middle (help-and-recovery may be inadequate if X4 has to follow a shooter cutting to the ballside corner, have X5 and X4 switch if they are interchangeable).
Canada Basketball - the point of the triangle should be on the foul line when the offensive team has a strong low-post game. An inverted triangle is stronger if the opposition shoots well from the outside or there is a defender who should be kept close to the basket,
Baldwin - if the offence puts 1 and 2 in the corners and two perimeter players in the guard slots, invert the triangle and bring X4 or X5 to the top, the bottom player is basically playing man-to-man (shown).
Winning Hoops - in this case, invert the triangle and move one of your post defenders to the elbow.
coachesclipboard.ca - triangle players remember the concept that "they have 3, we have 3". If they bring two up, we bring two up, the biggest player stays on the baseline.
Lamas - if an attacker near the baseline goes high on the perimeter, the low defender on that side comes up to the foul line. If 4 gets a pass and is not a good shooter, X5 covers but doesn't follow him. If 4 is a good shooter, X5 will play man-to-man and force 4 toward the middle, where X3 can help if 4 drives to the basket.
Where 2 and post 5 (not 1) are the scorers on the attacking team, a zone defender will collapse to help defend the ball if it goes to 5.
Here non-scorer 3 has the ball in the corner, and is area defended by zone defender X4. If 3 passes to 5, X4 will double team the post with man-to-man defender X1.
betterbasketballcoaching.com - if you use a big man to guard 5 and expect he will be low in the key a lot, consider flipping the triangle to have two players at the top and one at the bottom.
bbhighway.com - in some cases you might choose to go man-to-man on a post player, but from a defensive spacing standpoint this isn't very effective use of your players.