Why did the major fit disappear?

[thorvald]

[hv=url=https://www.bridgebase.com/tools/handviewer.html?lin=st||pn|Thorvald,~Mwest,~Mnorth,~Meast|md|1S9864HAK632DCAJ92,S752HQ875D9873CQ5,SJHJT4DAKT6CKT863,SAKQT3H9DQJ542C74|sv|o|rh||ah|Board%2011|mb|1H|an|Major%20suit%20opening%20--%205+%20!H;%2011-21%20HCP;%2012-22%20total%20points|mb|P|mb|2C|an|Forcing%20two%20over%20one%20--%2013+%20HCP;%20biddable%20!C;%2014+%20total%20points;%20forcing%20to%203N|mb|2N!|an|Unusual%20notrump%20overcall%20--%203-%20!C;%205+%20!D;%203-%20!H;%205+%20!S;%2015+%20total%20points;%20forcing|mb|3C|an|4+%20!C;%205+%20!H;%2011-21%20HCP;%2012-22%20total%20points;%20forcing%20to%203N|mb|P|mb|3S|an|13+%20HCP;%20biddable%20!C;%2014+%20total%20points;%20at%20best%20partial%20stop%20in%20!S;%20forcing|mb|P|mb|4D|an|Cue%20bid%20--%204+%20!C;%205+%20!H;%2021-%20HCP;%20!DA;%2017-22%20total%20points|mb|P|mb|5C|an|13+%20HCP;%20biddable%20!C;%2014%20total%20points;%20at%20best%20partial%20stop%20in%20!S|mb|P|mb|P|mb|P|pc|SK|pc|S4|pc|S2|pc|SJ|pc|SA|pc|S6|pc|S7|pc|C3|pc|C6|pc|C4|pc|CA|pc|C5|pc|C2|pc|CQ|pc|CK|pc|C7|pc|H4|pc|H9|pc|HA|pc|H8|pc|HK|pc|H5|pc|HT|pc|D2|pc|S8|pc|S5|pc|C8|pc|S3|pc|DA|pc|D5|pc|H2|pc|D9|pc|DK|pc|D4|pc|H3|pc|D3|pc|D6|pc|DQ|pc|C9|pc|D8|pc|S9|pc|H7|pc|CT|pc|SQ|pc|DT|pc|DJ|pc|CJ|pc|D7|pc|H6|pc|HQ|pc|HJ|pc|ST|]399|300[/hv]

[smerriman]

This one is really bizarre; I've never seen it before.

 

It's not even connected to the interference - if East passes, North goes even further and leaps to 4♠ as it has been programmed to self-splinter with any hand with 5 clubs (and 13+ total points), rather than ever show support for the major.

 

Seems it just prefers 9 card minor fits to 8 card major fits, and it just doesn't come up much since it's very rare that you not only have both, but find the minor one first.

[thorvald]

I just found another situation, where the major-fit vanished

 

[hv=url=https://www.bridgebase.com/tools/handviewer.html?bbo=y&lin=pn%7CRobot%2CRobot%2CRobot%2CRobot%7Cst%7C%7Cmd%7C1saqt92h3daqjcaqt2%2Cs73ha8752d9753c84%2Csk65h964dk4ckj973%2Csj84hkqjtdt862c65%7Crh%7C%7Cah%7Cboard%203%7Csv%7Ce%7Cmb%7C1s%7Can%7Cmajor%20suit%20opening%20--%205%2B%20%21s%3B%2011-21%20hcp%3B%2012-22%20total%20points%7Cmb%7Cp%7Cmb%7C1n%7Can%7Cforcing%20one%20notrump%20--%203-%20%21s%3B%206%2B%20hcp%3B%2012-%20total%20points%7Cmb%7Cp%7Cmb%7C3c%7Can%7Cstrong%20hand%20--%204%2B%20%21c%3B%205%2B%20%21s%3B%2018-21%20hcp%3B%2019-22%20total%20points%3B%20forcing%20to%203n%7Cmb%7Cp%7Cmb%7C5c%7Can%7C4%2B%20%21c%3B%203-%20%21s%3B%2010-12%20total%20points%7Cmb%7Cp%7Cmb%7Cp%7Cmb%7Cp%7Cpc%7Cha%7Cpc%7Ch6%7Cpc%7Chk%7Cpc%7Ch3%7Cpc%7Ch8%7Cpc%7Ch4%7Cpc%7Cht%7Cpc%7Cc2%7Cpc%7Cct%7Cpc%7Cc4%7Cpc%7Cc3%7Cpc%7Cc6%7Cpc%7Ccq%7Cpc%7Cc8%7Cpc%7Ccj%7Cpc%7Cc5%7Cpc%7Cs2%7Cpc%7Cs7%7Cpc%7Csk%7Cpc%7Cs4%7Cpc%7Cd4%7Cpc%7Cd2%7Cpc%7Cdq%7Cpc%7Cd7%7Cpc%7Cdj%7Cpc%7Cd9%7Cpc%7Cdk%7Cpc%7Cdt%7Cpc%7Cs6%7Cpc%7Cs8%7Cpc%7Csa%7Cpc%7Cs3%7Cpc%7Csq%7Cpc%7Ch2%7Cpc%7Cs5%7Cpc%7Csj%7Cpc%7Cst%7Cpc%7Cd5%7Cpc%7Ch9%7Cpc%7Cd8%7Cpc%7Cs9%7Cpc%7Ch7%7Cpc%7Cck%7Cpc%7Cd6%7Cpc%7Cc9%7Cpc%7Chq%7Cpc%7Cca%7Cpc%7Ch5%7Cpc%7Cda%7Cpc%7Cd3%7Cpc%7Cc7%7Cpc%7Chj%7C]399|300[/hv]

 

When I played the hand I bid 6♣ on the south hand, as the simulation in my head gave 6♣ good chances

 

But strange with that 5♣ bid.