I just came across this arresting sentence in The Satanic Verses, of all places:

“Turn your watch upside down in Bombay and you see the time in London.”

It appears this is roughly true: Because Indian Standard Time has an offset of UTC+05:30, an analog watch set to Indian time and read upside down will give the time in London — 10:10 becomes 4:40, noon becomes 6:30, and so on. The reverse is also true — a London watch read upside down will give the time in India.

Unfortunately the hand positions are only approximate, and the U.K. observes daylight saving time and India doesn’t, so just now it doesn’t work. Interesting idea, though.

06/16/2024 UPDATE: Reader Kieran Child points out also that the trick cannot work perfectly as described as we need to add 5 hours 30 minutes in one direction and 6 hours 30 minutes in the other. “By studying it for a while, you will see that going from UK time to Indian time only works when the minutes are between 31 and 59, and going the other way only works when the minutes are between 00 and 29. For times outside of these ranges, you will be off by one hour.” Examples are sometimes chosen to conceal this confusion. (Thanks, Kieran.)