Long suits work opposite fit

This was a wild deal at a Bridge Base Online duplicate. What do you think of the auction? What happened in five diamonds doubled after West led the heart seven?

The basic principle for North is that if he is willing to bid five diamonds, he should get there immediately. Bidding four then five gives the opponents a fielder’s choice -- double or bid higher -after they have already exchanged some information. Here, though, if North had jumped to five diamonds, would East have bid five hearts ( ending the auction) or doubled (after which West might have advanced with six clubs)?

Note that five hearts has to fail unless South strangely leads a spade. But six clubs is unbeatable!

Against five diamonds, West would have done best to lead his singleton. Double dummy, the contract goes down two if East wins with the spade queen and immediately gives his partner a spade ruff, then West shifts to a heart. If East cashes the spade ace before delivering the ruff, that results in down one.

At the table, though, unsurprisingly, West led the heart seven. Declarer won with dummy’s ace, ruffed a club, cashed the diamond ace, crossed to the diamond king and ruffed the last club. Then he exited with the heart jack. Now East should have led a high heart. Even if South were 4=2=7=0, giving a ruff-andsluff couldn’t cost. Instead, he cashed the spade ace (not fatal), but then he led his last club (which was). South sluffed his spade loser and ruffed on the board to make the contract.