This isn’t Rodgers and Hammerstein’s best musical. And the leading man can’t sing for toffee. Yet Bartlett Sher’s production of The King and I, arriving in London after a successful Broadway run, is a knockout. With her cut-glass vowels and visage, Kelli O’Hara owns the role of the 19th-century British governess who, hired by the bombastic ruler of Siam (the film actor Ken Watanabe) to teach his innumerable children the ways of the West, discovers her deeper task is to teach the King himself. As for Watanabe, he wields effortless presence and impeccable comic timing. Even his energetic mangling of his only solo number, A Puzzlement, seems in keeping with his conflicted character. The main puzzlement for today’s audience is how to respond to the story’s orientalist gist. My advice is to think of it more as a sex-war satire, with the implication that all men are on some level insecure potentates in billowing pantaloons. Then you can sit back and enjoy the lovely songs, the sumptuous staging and the strong supporting turns, especially from Na-Young Jeon as the lovelorn slave girl, Tuptim. Having stood to join the inevitable ovation, you’ll head out into the night whistling a very happy tune.