Which card and why

[nullve]

A deal (rotated 180 degrees for convenience) from yesterday's Zenith Daylong Reward (MP):

 

[hv=pc=n&s=sjt9743hqdaj4cat4&n=sk86hakj763dkq52c&d=s&v=0&b=11&a=1sp2h3c(twice rebiddable !c; 5-11 total points)p4c(2+ !c; 16- total points)5cp5dp5hp6sppp]266|200[/hv]

 

Trick 1: ♥2-♥3-♥5-♥Q

Trick 2: ♠J-♠A-♠6-♠2

Trick 3: ♥4-♥6-♥9-♠3

Trick 4: ♠T-♠5-?

 

Which card do you play from dummy? And why? (Opps are robots, in case you didn't know.)

[LBengtsson]

west not know south has ♣A. why lead ♥ at trick 3? if west had ♠AQ5 then a ♣ ruff in dummy would promote a ♠trick. I therefore play for ♠ split 2-2 and play ♠K from dummy trick 4.

 

If robot west has ♠AQ5 then they are more clever defenser than me.

[nullve]

west not know south has ♣A. why lead ♥ at trick 3? if west had ♠AQ5 then a ♣ ruff in dummy would promote a ♠trick. I therefore play for ♠ split 2-2 and play ♠K from dummy trick 4.

Yes, that was the point.

 

The full deal:

 

[hv=https://www.bridgebase.com/tools/handviewer.html?lin=st||pn|nullve,~Mwest,~Mnorth,~Meast|md|3SK86HAKJ763DKQ52C,SQ2H985D98CQ98732,SJT9743HQDAJ4CAT4,SA5HT42DT763CKJ65|sv|o|rh||ah|Board%201|mb|1S|an|Major%20suit%20opening%20--%205+%20!S;%2011-21%20HCP;%2012-22%20total%20points|mb|P|mb|2H|an|Forcing%20two%20over%20one%20--%205+%20!H;%2012+%20HCP;%2013+%20total%20points;%20forcing%20to%203N|mb|3C|an|twice%20rebiddable%20!C;%205-11%20total%20points|mb|P|mb|4C|an|2+%20!C;%2016-%20total%20points|mb|5C|an|5+%20!H;%203+%20!S;%2017+%20total%20points;%20forcing%20to%205S|mb|P|mb|5D|an|Cue%20bid%20--%205+%20!S;%2021-%20HCP;%20!DA;%2014-22%20total%20points;%20forcing%20to%205S|mb|P|mb|5H|an|Cue%20bid%20--%205+%20!H;%203+%20!S;%20!HA;%2017+%20total%20points;%20forcing|mb|P|mb|6S|an|5+%20!S;%2021-%20HCP;%20!DA;%2015-22%20total%20points|mb|P|mb|P|mb|P|pc|H2|pc|H3|pc|H5|pc|HQ|pc|SJ|pc|SA|pc|S6|pc|S2|pc|H4|pc|H6|pc|H9|pc|S3|pc|ST|pc|S5|pc|SK|pc|SQ|mc|12|]399|300[/hv]

Pretty aggressive bidding by GiB(W), btw.