Avoid misdefending when the declarer is a bad guy

[jahol]

This hand seemed to me interesting.

 

[hv=d=s&v=n&n=s765hk93da83ca1097&w=sk10843hq1072d96cj3&e=saj2hj54dk1052c862&s=sq9ha86dqj74ckq54]399|300|Scoring: IMP[/hv]

 

The bidding just simple, south opening with one di, north 2NT, south 3NT. Opponents passing. The lead dia2, played small, nine, ace. The problem is obvious - how to avoid loosing one dia and four or five spade tricks before taking nine in dia, hearts and clubs. Played dia back, jack took the trick. Now...played spade 9, covered with ten, "ducked". Back king of spades...mission impossible became possible.

 

After the game, was just looking to the way, the same board was played at the other tables. The game was made at half of tables, mostly simple mistakes of the defenders, but one approach was even much more interesting than mine. After the same bidding, the declarer (north) got small H lead and ducked the H ten! "Obvious" H back was taken with ace, dia K was given to the opponents and they "cleared" H suit. Game made!

 

Can experts give me some logical explanation, which way real expert can avoid misdefensing the game in the first and second case demonstrated? Thank you very much.

 

(Not English, sorry for my english, hope, the meaning of the text is clear).

[EricK]

In the first instance, West has a perfect count of the hand after the opening lead!

 

Partner has led his 4th highest ♦ so has a 4 card suit. He is very unlikely to have a 4 card major as he would have preferred that lead to lleading dummy's suit. Declarer has also denied a 4 card major for his bidding. Hence East must be 3-3-4-3 and declarer 3-3-3-4.

 

Now West should ask himself why declarer is playing on ♠ and not ♣, and why he played a small spade away from his Q and then ducked the T, rather than leading up to the Q. It is clear that he doesn't have Axx or AJx to play that way so he is fooling you.

 

As an aside, East can also work out that declarer doesn't have Kxx or KJx in ♠, so should overtake the T with the J, and play A and another ♠.

 

In the second case, East will have a count of the hand: Partner will have shown a doubleton ♦ and 4♥ (his ♥ return will have shown count). The bidding will show declarer has 3 ♠ (at most) and so partner has 5 of them.

 

Now, from the bidding (North's 2NT) he knows that partner has one high card outside of ♥Q. If it is ♣A, then he can afford to cash ♠A before setting up the ♥ and get attitiude signal from partner, because declarer can not possibly have 9 tricks. If partner's high card is ♠K, then it is necessary to cash out in ♠ because declarer has 9 tricks (4♣, 3♦, 2♥).

 

Eric