Cashing the Winner in the Both Suit?
If you have a winner in the both suit, and an entry in the other hand, you usually want to be trying to run a compound squeeze. So, most typically, there is no winner in the both suit. But there are other possibilities -- the winner in the both suit might not have an entry opposite, or it might but there is not enough communication for a compound squeeze.
But suppose you do have a winner lying around in the both suit. There was one example above where it was useful. Otherwise, as far as I know, you should cash the winner as soon as you can.
In the both-finesse position:
On the first spade winner, Righty throws a diamond. You now have a double squeeze with hearts as the both suit, failing because of that diamond winner on the board that needs to be cashed before the last free winner.
If there was a diamond entry to the board, the double squeeze could be revived by going to the board in diamonds and coming back in clubs. But that exception to the rule simply makes the rule: If you can cash the winner in your both suit after cashing one round of your free suit, you can save the situation. But you would have been better off cashing it sooner. (And, if there was a diamond entry to a winner on the board and an entry back, you should have been running a compound squeeze.
So, it seems paradoxical, but as far as I know, a basic principle of double-guard squeezes is usually to cash your winners in the both suit before starting your squeeze. Cashing them will also probably help reveal the position in that suit.
Here is an actual hand from 8/7/08, matchpoints. Dummy had opened 1NT, RHO overcalled 2D, and declarer ended up in 4S. The opening lead was a diamond
Declarer played the queen of diamonds, forcing out the ace. Righty now tried the deceptive lead of a small club, but declarer was happy to duck to the jack and even happier when that won the trick. What now? (This is your chance to figure it out for yourself.)
The answer is a double guard squeeze. There is a known single threat against Righty. There is no compound squeeze because of the lack of a diamond entry. But the double squeeze works. However, to make it work, you have to cash the queen of diamonds before leading the third spade to hand.
Now let's try to do better than Love. Love gives this hand:
You are in 7NT with an opening lead of the J of diamonds. You desperately need a single threat, spades is essentially the only possible suit (because Lefty would have lead a heart having both the king and queen), and in fact Righty pitches the queen of spades when you play the ace of spades. Maybe Righty has QJ10; maybe Righty just has the jack and Lefty will pitch the 10.
Usually, there is no compound squeeze because there is no entry in one of the potential both suits. In this case, the problem is that there is no way to get back to hand to cash the final squeeze card.
So, as Love notes, if Righty has both heart honors, you have a simple squeeze -- cash the ace of diamonds and then run the clubs. However, if the heart honors are split, you are in the curious situation of Righty having to guard against a finesse in both suits. Just cash the clubs and you will be able to read the situation at the end easily. (If Righty pitches a heart honor, you can safely finesse in hearts; if Righty pitches a diamond honor, you can safely pitch in diamonds. For either, you first cash your spade, so Righty has to save two spades.) Playing for split heart honors is the better percentage (67%).
However, if you want to run a double guard squeeze, my rule is to cash the honor in the both suit first. Here, it can do no harm if you cash your diamond honor first. If you cash your heart honor first, it is even better -- you lose nothing if the honors are split, and if Righty has both heart honors, then it is a guard squeeze instead of a double guard squeeze.
And because the diamond situation is obvious and you can't misguess the spades, the jack of hearts was a chimera. With a small heart instead, you would play it as a double guard squeeze.