Playing a grand slam, not against Jeff Smith

This hand was going to be one I loved or hated.  Let me set it up for you.  I held S KQJ53 H 7652 D K62 C 8

We are vulnerable against not and Colin opened 1C strong.  I bid 1H showing a positive response with five spades or a balanced hand with 11-13 HCP.  Colin bid 2H which shows at least four card spade support and is unlimited. 

Now RHO bid 3C. What does this mean?  Is it lead directing?  Why would you bid 3C now and not over 1C?  This was an established partnership so they had agreements here. 

We have had some discussions that in this type of auction we play serious 3NT so probably 4C doesn’t show extra and it seems unlikely to deny all red suits.  I tried that.  West on my left bid 5C and partner bid 5NT grand slam force.  What should I bid now?  I missed the best bid at the table.  I should bid 7C.  It must be asking partner to play the hand from his side and  that has to be right.  I bid 7S and set myself up for what was to follow.

The opening lead was the C3, East playing the C2.  My job (and yours) is to find the diamond queen.  You play a spade to the King and a spade to the S10.  East shows out throwing the C5.  You play three rounds of hearts and all follow the hearts are 3-3.  You cross to your hand with the SQ and play the last heart.  The opponents throw clubs.  You know play off another spade and East throws the CQ and West the CJ.  When you play the last spade something funny happens.  East throws the D3 and West throws the C4.  West has been playing pretty random spot cards through this whole process.  It seems very likely that East held S 9 H 1043 D ?X3 C KQ10752.  Who has the DQ?

First I tried to decide if East was more likely to bid 3C (the second time round) with or without the DQ.  It didn’t really seem to matter.  Could East really have only five clubs and hold four diamonds?  So he held Q10752 Q943 in the minors.  No I couldn’t believe that he would do this on such a rotten suit.  Why was he throwing a diamond?  Did he have the queen and want to confuse me?

My experience here is that most people don’t throw a diamond from QXX.   Jeff Smith might do it.  He loves getting me on plays like this.  But he wasn’t at the table.  So if you played West for the DQ you were right.  I however blew it.

Why should we play it Colin’s way (apart from the fact that he guesses better)?  With Colin as the closed hand he has the opportunity to lead the DJ and see if East will cover.  With dummy exposed that really isn’t much of a chance.