[shyams]

Playing IMPs against bots, this came up:

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As usual, Robot North finds a weird opening lead of ♣8. Dummy plays ♣Q, you win with the ♣K as declarer plays ♣2.

Clearly, it is time to switch. Which suit and which card?

Caution: The problem may not be very instructive. I thought I made the right play only to find that my choice was not winning.

[nige1]

shyams 'Playing IMPs against bots, this came up: As usual, Robot North finds a weird opening lead of ♣8. Dummy plays ♣Q, you win with the ♣K as declarer plays ♣2. Clearly, it is time to switch. Which suit and which card? Caution: The problem may not be very instructive. I thought I made the right play only to find that my choice was not winning'.
++++++++++++++++++++
My guess: ♦AT, hoping GIB that has KJ9xx and isn't bogged down in its new Double-dummy Misère mode.

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[AL78]

nige1, on 2020-October-06, 10:38, said:

shyams 'Playing IMPs against bots, this came up: As usual, Robot North finds a weird opening lead of ♣8. Dummy plays ♣Q, you win with the ♣K as declarer plays ♣2. Clearly, it is time to switch. Which suit and which card? Caution: The problem may not be very instructive. I thought I made the right play only to find that my choice was not winning'.
++++++++++++++++++++
My guess: ♦AT, hoping GIB that has KJ9xx and isn't bogged down in its new Double-dummy Misère mode.

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I'd go for that as well, though if that was the layout, why did North not lead a diamond?

[shyams]

Well, I switched to the 9 of hearts. I spent some considerable time before I played this card.

Interestingly, the switch suggested by nige1 and seconded by AL78 works wonders. Partner did have ♦KJxxx.

[AL78]

shyams, on 2020-October-07, 05:08, said:

Well, I switched to the 9 of hearts. I spent some considerable time before I played this card.

Interestingly, the switch suggested by nige1 and seconded by AL78 works wonders. Partner did have ♦KJxxx.

Amazing. Playing with one of my regular partners this problem would not arise, because they would have led their fourth highest diamond (as would everyone else defending the same contract and same declarer).

[shyams]

AL78, on 2020-October-07, 08:16, said:

Amazing. Playing with one of my regular partners this problem would not arise, because they would have led their fourth highest diamond (as would everyone else defending the same contract and same declarer).

Agreed. This is what caused me to caveat with a title and additional description in the OP. The bots do tend to make weird opening leads.

The way I saw it, declarer was likely to be 3=3=5=2 OR 3=3=4=3 (bots rarely/never bypass a 4-card major to bid 1NT). In reality West GIB held 3=3=3=4 and partner had divined to lead top of doubleton!

I thought my switch to ♥9 was sound. I still am unsure if I made the right switch (in principle).

[johnu]

AL78, on 2020-October-06, 11:07, said:

I'd go for that as well, though if that was the layout, why did North not lead a diamond?

As OP noted

Quote

Playing IMPs against bots, this came up:

Those leads are what GIB does all the time.