September 1, 2018 at Adventures in Bridge, Hand #12 gave defensive insights.
West (Dummy): ♠104 ♥Q9843 ♦J743 ♣85
North: ♠92 ♥AK1075 ♦965 ♣K62
East (your LHO) opened 1♠. Partner passed. RHO (West) passed and you bid 2♥ with the North hand. East rebid 2♠ and everyone passed. Partner led the ♥2, which was an obvious singleton when Dummy came down with five hearts. You won your ♥K and took stock. There are circumstances in which playing a LOW heart next would be the correct play. You know partner will ruff Declarer's ♥J and that ensures the heart suit in Dummy can never provide any discards. However, there are two reasons NOT to do so here: (1) Declarer is unlikely to be able to pull trumps and get back to Dummy for a heart trick with such a weak Dummy; (2) Partner is likely to have three spades on this auction and might be ruffing with a natural trump trick, e.g., ♠Qxx which would collapse two of Declarer's losers into only one.
You are NOT going to play the second heart yet, because that trick cannot go away. So, what should you do next? Declarer should have six spades on the auction and is known to have two hearts. So, his distribution is probably 3-2 in the other suits. Based on Dummy's holdings (4 diamonds and two clubs), Declarer is more likely to have three clubs and only two diamonds. If Declarer has only two diamonds, there is no rush to lead a diamond for partner from your side of the table. However, if Declarer has three clubs, then the ONLY useful feature of Dummy is the doubleton club. Put a trump on the table at trick two\, aiming to prevent a club ruff. Partner should give you trump suit preference as to where her cards are—her the ♠7 showing a preference for diamonds over clubs. If Declarer takes the trump and leads the ♥J, partner will ruff that if she does NOT have a natural trump trick, and lead her third trump. If partner does not ruff, you take the ♥A and return your last spade. Even if partner fails to ruff the ♥J, she will be able to ruff the ♥Q if Declarer allows the ♠10 to win in Dummy and attempts to discard on the ♥Q. In the fullness of time, your side gets two club tricks, one diamond, and two hearts. Unless you return a trump right away, Declarer will get a club ruff in Dummy and take nine tricks.
6-5 Hands Do NOT a Weak Two Make
North: ♠AJ10943 ♥83 ♦— ♣J10853
South: ♠KQ76 ♥AQ942 ♦AJ104 ♣—
Although it is tempting to open the North hand 2♠, it is incorrect. A Weak Two bid (or a 3-level preempt) shows a one-suited hand. A 6-5 hand has too much extra playing strength to ignore your second suit. Plus, sometimes partner is void in your 6-card suit, but has a great fit with your 5-card suit. If North succumbs to temptation, partner will query with 2NT (asking for a feature). Have found no Ace or King opposite, South will give up with 4♠. (South is envisioning partner's hand—six spades to the ♠AJ10 and the remaining cards are most likely to be 3-2-2 or 3-1-3 in some permutation. From her point of view, slam require split honors in diamonds AND the heart finesse to work. That is not good odds for a slam.)
By contrast, if North passes, South will open 1♥. North can bid 1♠. South will jump to 4♣—a splinter in support of spades, showing 4 trumps and the equivalent of 20 HCP. After that, getting to 6♠ should be trivial. Incidentally, the 7♠ contract that Deep Finesse tells you is makeable requires taking the heart finesse. If you plan to set up hearts in Dummy, you will still have a losing diamond or club in the end game. If you play on a cross-ruff, someone will get a trump in the end. Don't beat yourself up about what Deep Finesse says when it involves KNOWING that a finesse will work—or to drop an honor offside, etc.