Perplexity

"You're an odd chap, Watson," said Sherlock Holmes. "A couple of weeks ago you claimed to be twice the man I am. HOLMES plus HOLMES equals WATSON, you said, and that LAWS was your pin number. Well, from that information, I can't tell whether your pin is 5729 or 7348."

"I try one, then the other," said Watson. "They give you three goes."

"Well I think I've got your number," said Holmes, "and it shows I'm twice the man you are." It's WATSON plus WATSON equals HOLMES that you should be working out."

"Surely there's more than one answer to that, too," said Watson.

"But as I said," added Holmes, "you're an odd chap, Watson."

Can you help work out the value of WATSON? Answers, by 7 August, to: Perplexity, The Independent, 1 Canada Square, Canary Wharf, London E14 5DL.

This week's Chambers Dictionary winner: Paul Terry (Wokingham).