nate_m

In context it obviously means pick up KJxx onside for one loser.

Your statement indicates that you don't see the restricted choice. Your argument is essentially the same as somebody who says "I have Axxx vs K10xxx and see the J fall, hooking wins vs. J and rising wins vs. QJ, why anything to do with the Q relevant?" Of course, if you hook every time you see an honor, you win vs. Q, J, and only lose to QJ, and that must be taken into account. After low to the 9 and J/10, you cannot pick up 4-1 splits but rising ace wins vs. KJ and K10 offside, losing only to J10 offside. That's "twice as likely." You do lose an extra undertrick on the 4-1 splits, so it's not quite 2 to 1. This all assumes the opponents never find high from 10xx or Jxx. All this was ofc already noted by mikeh above.

If you have 3514, just tank before you bid 3S.

NO.

What? No. Look, you have a flat 13 count with a dubious club queen and your partner has denied holding substantial extra values. It doesn't matter that you are control rich, you sign off because slam is really unlikely to be very good. If you bid 4D here, partner holding a hand like ♠Qxxx ♥AKxxx ♦ Kx ♣ Kx, which is a rather big hand for a nonserious 3NT, will keycard and bid the slam. It will have no play. Not signing off with the North hand opposite an advertised minimum is totally insane. On the actual hand not being in slam is fine. You are off an ace and a key queen. It's true we'd rather be there than not, but such is life. If anybody has to bid more, it is the 6-5 hand with all the tricks.

I'd pass with the death holding in spades.

No. Just think about what you pick up vs. what you lose to. If you hook every time you see an honor you blow to J9, 109, J10, and J109 offside while picking up J, 10, 9 offside. The particular honor played should not affect your decision.

I would frequently bid a 3 card suit in this auction.

It's clear to bid 8♣ with such a good suit.

I mean if RHO has the spade guard, the diamond ace, and the QJ of hearts we are making in style. I don't like my chances but I'll play for that by running clubs.

I mean, with the example hands suggested in the post above, it's hugely likely LHO shifts to their stiff minor, so they can basically be discounted. Flying the ace from AJxx on the second spade from hand is a novice play, as it is successful on 0 layouts, blows a trick in practice on almost every single possible layout, and as a bonus is consistent with general principles (second hand low). Playing low is something I would expect any non-beginner to find, so I would estimate your odds of picking up AJxx on an egregious misdefense and a trump coup as near zero vs. human opponents who don't have issues following suit. You are playing against robots, so you might see the A from AJxx a fair bit of the time. Fun fact: If the robots play the A from AJxx 100% of the time, you break even on your line. If the robots EVER duck AJxx, my line is better, if we assume opponents shift to a stiff minor.

It's far from obvious to me that playing a top spade first is better. If trumps are 1-4, hooking on the first round picks up any stiff but the jack. If trumps are 2-3, playing a top spade first doesn't help, as when it loses you intend to finesse E for the jack of spades anyway, so you still lose to any doubleton with the jack. If trumps are 1-4 and you bang a top spade first, you pick up stiff jack offside (360 layouts). However, after the top spade loses and you win the return and run the 9 getting the bad news, you need 3 rounds of diamonds to stand up for the trump coup to operate. On 840 layouts (West 1732 without stiff jack) you will now fail, whereas running the 9 would have succeeded. The preceding analysis assumes West would have shifted to a minor suit singleton if they had one, which is not IMO a totally crazy assumption to make. I appreciate hearing that you do not believe my line to be optimal. What line do you prefer, and why do you prefer it?

Well West shifted to a spade after 2 rounds of clubs which is atrocious, as I was probably booked for down 2. Additionally, since I have shown 6 diamonds I don't have, West might be inclined to play me for 3163 distribution and keep diamonds instead of hearts when not 1543. That is a disaster on the actual layout. To avoid having to guess whether or not I have stranded the ace of hearts, West could continue a heart instead of playing the diamond queen after I duck the heart. This clarifies the heart position. Once declarer follows twice, West with 3 diamonds must play partner for a diamond guard.

It's far from "of course" to duck the heart. It's not unreasonable to win it and lead a diamond, planning to duck a diamond to East. This wins if diamonds are 3-3 and East holds the queen. In fact, this is probably the right play, but you did not give us the option to select it. Of course, you have given us the hand AFTER the key decision was made. Now you have no choice but to run all your winners and hope that West is 1543 or that West does something terminally stupid in the endgame. That said, the opponents could have easily beaten the hand, possibly by multiple tricks, had they just continued clubs like any sensible bridge player.

Cross in diamonds, run the 9 of spades is my instinct. Let's see how it plays out... I think that West has 7 hearts and no stiff minor, else they play it at trick 2. I ignore the HCP requirements for preempts because in my experience they aren't that accurate. Therefore, the probable shapes and the number of combinations associated with them as I see it are: Shape 1732: 1050 1723: 1750 2722: 2100 Running the 9 of spades wins in 3580 cases (picks up the 4-1s that aren't stiff J and 3-2s with J onside) and playing low to the KQ (or low to the K then finesse 10 if it loses, as I don't recall robos ducking from Ax, so we'll assume that works) wins in 2370 cases (stiff J offside plus all 3-2s but AJ doubleton off). Under these highly restrictive assumptions running the 9 is percentage. Of course, my assumptions are far from 100% but that would be my line.