What do you think of that bidding? Well I will be polite. Awful! Lanquishing in 1NT when a cold vulnerable game is available is not going to be well received by your team mates.

East/West's core system was a strong no trump with 5 card majors. So nothing wrong with the first two bids as the 1C opener has to be used in the absence of the 5 card major. But then the 1♠ rebid. Bidding is supposed to be a "conversation" between partners describing both the strength AND shape of their hands.So why the 1S bid when opener could rebid 1NT to show his balanced 12-14 HCP hand? Apparently the partnership were not playing checkback (or a form of Crowhurst) so if 1♠  was not bid the potential spade fit would be lost. Checkback resolves the potential losing a major suit fit problem, and ensures all 4/4 major suit fits and 5/3 major suit fits can be found after a 1NT rebid by opener. A bid of 2♣ after the 1NT rebid should show at least intermediate values and asks the opener to describe his hand further with reference to the majors. The response identifies the lower or upper range of the 1NT rebid and whether a 5/3 or 4/4 fit in a major exists. The opponents at the other table were playing exactly the same core system.but their 3rd bid was 1NT as they were playing checkback.

Going back to the highlighted bidding sequence, what about responder's rebid of 1NT? Indescribable as far as I am concerned. A natural bid of 2♣ was available to West but it would have been forcing and showing at least intermediate values. Anyway after 1NT was bid to show a limited hand with 6 to 9 points, the auction not surprisingly came to a rapid conclusion. Personally even if I had been playing their system, I would have slightly overbid my hand with a rebid of 2♣.

The opponents in the other room though were in far better shape and West had a lot of information about East's hand as he considered his rebid.West didn't use checkback as he thought he was at this stage a little too weak for the bid, but satisfied himself with a 2♥ rebid, content to play there as he knew there was a minimum of a 5/2 fit after East's 1NT rebid. East raised to 3♥ with a maximum and a wonderful 3 card fit. Once again after East's descriptive 1NT rebid, West knew there was a 5/3 heart fit and that there would be at least a partial fit in clubs. He was stronger than he might have been so it was an easy raise to 4♥. The play of the hand was also easy and a gifted vulnerable game swing was secured. 

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