Ron Klinger from Australia is a leading teacher, writer and player. He has probably lost count of both the number of times he has represented his country and the number of books he has written. His latest work is "Playing Doubled Contracts" (Weidenfeld & Nicolson).
Klinger packs a lot of material into a short space. There are 58 quiz questions and answers in 96 pages. In today's diagram, look only at the auction and the North-South hands. Against four spades doubled, West leads heart king and continues with the heart queen. East overtakes with his ace and shifts to a low club. How would you plan the play?
East's pre-empt was in the modern style - open high with a long suit and a weak hand, almost regardless of suit quality and vulnerability.
Unless you are sacrificing, a double often tells you that the trumps are breaking badly. This can help you with the play - as here. What can West have for his double but all four trumps?
Suppose you run the club to dummy's 10, cross to your hand with a diamond, and lead the spade two. If West crazily plays his four, cover with dummy's five. A rational West will put in his spade 10, thinking this assures him of two trump tricks. However, you can endplay West.
You must reduce your trump length. Win with the spade ace, cash the diamond ace, ruff a diamond, play a club to the queen, ruff a diamond, and cash the club ace, bringing everyone down to three cards. Now lead the club king. West must ruff high, but then has to lead from his spade queen-four into your king-eight.