Gib missed the ruff

[finesse157]

I think I am missing something here, but why would you not give a ruff when all the Diamonds are known

 

https://www.bridgebase.com/tools/handviewer.html?lin=st||pn|,~~v3fakebot,~~v3fakebot,~~v3fakebot|md|1SAQJ973HJ6DJCK632,S6HKQT874DKTCA954,SHA953D976542CJT8,SKT8542H2DAQ83CQ7|sv|e|rh||ah|Board%203|mb|1S|an|Major%20suit%20opening%20--%205+%20!S;%2011-21%20HCP;%2012-22%20total%20points|mb|2H|an|Two-level%20overcall%20--%205+%20!H;%2010+%20HCP;%2011-18%20total%20points|mb|P|mb|2N|an|11-13%20HCP;%20stop%20in%20!S|mb|P|mb|4H|an|13+%20HCP;%20strong%20rebiddable%20!H;%2014-17%20total%20points|mb|P|mb|P|mb|P|pc|D5|pc|DQ|pc|DJ|pc|DT|pc|H2|pc|H6|pc|HK|pc|HA|pc|CJ|pc|CQ|pc|CK|pc|CA|pc|HQ|pc|H5|pc|S2|pc|HJ|pc|HT|pc|H3|pc|S4|pc|S3|pc|DK|pc|D2|pc|D3|pc|S7|pc|H7|pc|H9|pc|S5|pc|S9|pc|CT|pc|C7|pc|C2|pc|C5|pc|C8|pc|ST|pc|C3|pc|C4|pc|D9|pc|DA|pc|SJ|pc|S6|pc|D8|pc|C6|pc|C9|pc|D7|pc|S8|pc|SQ|pc|H8|pc|D6|pc|H4|pc|D4|pc|SK|pc|SA|

[thorvald]

GIB simulated, that partner had no more trumps

[finesse157]

I thought that, but that would have given south 5+ clubs. I gave the simulator the trump void hand, and a few hands with 5/5 S/C. My simulation still gives 60+% for the ruff.

[smerriman]

Nah, it's not that at all. It's just the usual situation of GIB not making any deductions / assumptions based on past played cards. So even though there is a 0% chance you would have played the ♦J on the first round with ♦KJ, it simply doesn't know that.

 

In fact, quite the opposite - when deciding what to play at trick 3 it thinks there's about a 65% chance you have the ♦K to make up the points that S/W have shown.

 

(I've said a few times in the past on the forum it used to have this type of logic built in when Ginsberg originally programmed it, but it got removed for being too slow / not working properly).