Most players play ‘fourth suit forcing’ but what does it mean?

        ♠  10 4 3 You open 1♥, partner bids 1♠.

♥  K Q 10 5 3 You rebid 2♣ and partner bids 2♦.

♦  A Alert, fourth suit forcing.

♣  A 8 7 4 What next?

Well, we have a diamond stop, so is it an automatic 2NT? No, a better bid is 2♠. Our 2♣ said we hadn’t got 4-card spade support, so our delayed support shows only three cards. We have already shown 5-4 in hearts and clubs– so 2♠ shows the shape perfectly.

  Partner will bid 4♠ with five spades (or perhaps even make a slam try). But with only four, partner will find another bid.

  So, fourth suit forcing doesn’t simply mean ‘bid No Trumps if you’ve got a stop’ (though of course, you would bid No Trumps if instead you held  ♠ 4,  ♥ K Q 10 5 3,  ♦ K 10 7,  ♣ A 8 7 4). Rather it says ‘there’s game here somewhere but I’m not sure where’.

Think of fourth suit forcing merely saying ‘keep going; tell me more’.