Progressive squeezes made "easy"

You may have noticed I like squeezes. Recently there have been 2 unusual progressive squeezes, here and [add link].

The end positions are repeated here with slight modifications (in both cases, East's hand is immaterial except where noted):

		♠	A 10 8
		♥	2
		♦	7 4
		♣	2
♠	K J 9
♥	J 9 8
♦	10 9
♣
		♠	Q 2
		♥	K 10 7
		♦	A
		♣	K

In this position, West has already come under pressure and still needs to discard. Declarer has 4 top winners, but can emerge with 6 of the last 7 tricks.

If you switched the SK and SQ, this could be played as an ordinary repeating squeeze: 3 threats, 2 of them over the defender, and enough entries that whatever is unguarded can be cashed to effect another squeeze (ignoring, for the moment, that there are immediate 2-trick threats in both majors). Just cash DA (optionally can be delayed) and CK: if hearts are unguarded, HK, HT effects a diamond-spade squeeze. If spades are unguarded, SK, SA, ST effects a red suit squeeze. If diamonds are unguarded, SK, SA, D7 effects a major suit squeeze.

This might also work if you could duck a heart and a diamond came back -- now the count would be rectified and all the necessary entries are in place. But, a savvy West knows that the key to progressive squeeze defense is to give up the trick that doesn't allow a subsequent squeeze. In this case, if in with H8, West can exit SK, giving up a spade trick, but preventing the red suit squeeze.

This is similar to the reason why a normal progressive squeeze needs 2 menaces over the defender. If there's only one, they can normally unguard that menace and then there's no 2nd squeeze since both remaining threats are under the defender.

If that's the key to progressive squeeze defense, then the key to setting up more complex progressive squeezes is to find enough compensation to prevent defender from breaking up the 2nd squeeze. One standard technique is a 2 trick menace, such as the heart suit above. This is "commonly" used when there are 2 menaces under the defender, a 2-trick squeeze will still succeed if the sole "over" menace is a 2-trick threat. The defense may prevent a 2nd squeeze by unguarding that menace, but it's small consolation when that immediately costs 2 tricks.

In the position above there's all sorts of compensation that's necessary:

a) the heart tenace: if West unguards diamonds, DA, SA, D7 effects a major suit strip squeeze. This would not work if the HT and H9 were switched.

b) the heart establishment threat: if West comes down to 2 hearts, we can duck a heart to set up 1 extra trick, then win the (forced, see below) red suit return for a diamond-spade squeeze. Without the H7, the squeeze fails.

c) the split tenace in spades: this is necessary to prevent a spade return in (b), this breaks up the 2nd squeeze but at the expense of conceding an extra spade trick.

d) the 2-trick threat in spades: this is not strictly necessary, but it does mean that if West errs by blanking his SK he won't take any tricks (DA, 3 spades for a red suit squeeze). The 2-trick threat in hearts is similar.

More recently I posted this club grand slam:

		♠	Q
		♥	K
		♦	A Q 7 4 2
		♣
♠	A
♥	Q J
♦	K 10 8 6			♦	J 9 5
♣
		♠
		♥	10 9 8 7
		♦	3
		♣	5 2

(Note East has 3 diamonds here.)

Declarer has 5 tricks (including the diamond finesse), but by cashing a club can again emerge with 2 extra tricks.

Here, declarer appears to have a useful entry in the diamond suit, but needs to ruff a diamond to isolate the menace against West, so that's somewhat of an illusion. There's an entry in hearts, but it's blocked, and there's no entry in spades. But, the ruffing threat in diamonds and the blocked heart position looks like a trump squeeze. In fact, if West pitches the SA on the next club, then DQ, SQ does subject him to a red suit ruffing squeeze (if heart, HK, ruff, hand good; if diamond, ruff diamond, HK, dummy good).

So, a spade pitch is out. What about a heart? Declarer can unblock the HK, get back to hand with a ruff, but then will lack either an entry or a menace for the spade-diamond squeeze. But the 2-trick heart menace bails him out, and is in fact necessary.

What about a diamond pitch? There's no major suit ruffing squeeze since the spade length for a ruffing threat isn't present. Even if it were (e.g. make a diamond a spade), establishing a diamond requires a ruff, and then only the HK is left for an entry to cash the established diamond, but using the HK would break the intended major suit ruffing squeeze. Luckily (for declarer) there's a 2-trick threat in diamonds, too. (Earlier in the play, declarer had to be careful to pitch a spade and keep all 5 diamonds.)

Note that if East didn't have a 3rd round diamond guard, then declarer could have won the opening heart lead in dummy (preserving HA in hand) and would again have a more typical progressive squeeze:

		♠	Q
		♥	3
		♦	A Q 7 4 2
		♣
♠	A
♥	Q J
♦	K 10 8 6			♦	J 9
♣
		♠
		♥	A 10 9 8
		♦	3
		♣	5 2

The red suit length looks nice, but isn't really necessary: cash 2 clubs and then whatever winner LHO unguards for a repeating squeeze. So that 3rd diamond with East really messed things up and required 2 2-trick menaces and a trump squeeze to compensate.

The general point I wanted to make here (not sure if I was really successful) is that I find most squeeze books misguided. Perhaps BLUE or whatever is useful when first learning a simple squeeze (B = Both guards in one hand, L = right number of Losers, U = at least one threat in the Upper hand, what I call "over", E = Entry to established winner available), but in the long run enumerating requirements without motivations is not helpful.

For example, to me, the requirements for, say, a compound squeeze are just: a triple squeeze against one opponent such that whatever they do you can effect a double squeeze -- reading some crazy list of possible entry configurations that amounts to the same thing does not do much to provide insight. If there's some defense, or lack of entry, or whatever, that wouldn't allow a double squeeze to develop, then you need some compensation that prohibits that defense. In the first deal above, you can't rectify the count, LHO might attack your entries, and so forth, but once you start bringing the HT, SQ, and long heart into play you have a counter for all these things. It would be impossible to memorize something like "3 losers, a split tenace, a tenace and establishment threat under the defender, control but not necessarily a useful entry in the 3rd threat over the defender, etc" and have that be useful. (Not that any of this is that useful, of course.) I find it much more productive to start imagining it as a "normal" squeeze, then as flaws are identified look for compensation.

That said, enumerating squeezes can be very useful as an exercise -- I think I have a very firm grasp of double squeezes (and how to defend against them) as a result of enumerating all the compound squeezes, but I haven't bothered to memorize my list of compounds.