Bidding
Open 2NT showing 20-22 HCP and no five card majors and no singletons or worthless doubletons. Partner bid
3C a Stayman bid straight after a NT opening bid looking for 4 card major suits. You bid 3H showing your 4 card heart suit, (remember 3D is the negative response by you saying no 4 card majors), partner bids 4H.
Acol Bidding
Open 2NT showing 20-22 HCP and no five card majors and no singletons or worthless doubletons. Partner bid
3C a Stayman bid straight after a NT opening bid looking for 4 card major suits. You bid 3H showing your 4 card heart suit, (remember 3D is the negative response by you saying no 4 card majors), partner bids 4H.
Your points are looking really good 20+ 7 = 27 HCP! but your loser count is dire. Three in spades - 1 in hearts- 2 in diamonds and none in clubs. Six losers.
Lose to the AS and win with the KS return. Play AH and then a low club to dummy's AC. A second round of trumps to your hand then lead out the KC and QC where you discard the spades on the table. west trumps in but it's too late - the QH ruffs your loser small spade (2 losers in one trick gone) and leads back another spade which you ruff. Play a low diamond up to KD which loses, but the ret of the tricks are yours
This is an example of a contract that has more than sufficient points and cards in suits - but cannot be made if you cannot stop the opposition leading their spade suit.