[uva72uva72]

My link

IMPS, ACBL robot individual

Difficulties in handling of balanced hands in balancing position have been documented recently, to the effect that South has no way of bidding hands in certain ranges. This hand documents an issue in North's responses to a balancing bid of 1NT. In this instance, 1NT showed 11-15 HCP (over a 1♣ opening the notes say 11-14 - see earlier posting "Yes Virginia there is a gap"). North passes, knowing that N/S have 23-27 HCP as a partnership, and misses a shot at a very high-percentage vulnerable game at IMPs.

However, if South doubles, guaranteeing only 9 HCP, North invites while knowing that the partnership could have as few as 21 HCP.

My link

Predictably, 3NT is much easier to play with the South hand, since West must lead. North as declarer must win the ♥10 opening lead with the ♥A or the contract fails. 7 of 8 3NT declarers failed to make that play and went down, whereas 3NT from the South hand virtually plays itself.

Note that the balancing 1NT call does not give up on a ♠ game since systems are on over balancing 1NT.