East hopped with the ace to return another diamond for the king. South led a heart to the king followed by another for the ace on which West showed out. A spade loser was inevitable and East was entitled to the trump queen but ten tricks were home, N-S +620.
There was no particular reason for South to finesse East for the queen of hearts but he was restricted to the contract by playing trump from the top. The early play disclosed that West surely held five diamonds making East a slight favorite to hold the heart queen. If South knew that diamonds divided 6-2, then East becomes a strong candidate to own the trump queen because he holds eleven empty spaces to West's seven.
North's artificial response functioned as a Bergen raise revealing four-card heart support but less than a limit raise. South then advanced to the major suit game confident of a nine-card fit.
Some players would open 1NT with the South hand but this action would not alter the final contract. North would employ Stayman to uncover the heart fit and the major suit game would be reached when North offers an invitation by raising to three hearts.