Hat-Cheque-Point-Charlie

Almost every word in the English language derives from shah.

Once upon time there were shahs. Some shahs were happy shahs. Other shahs were crippled or dead. In Persian that meant that they were Shah mat. Shah went into Arabic as shah (ain’t etymology fascinating?). That went into Vulgar Latin as scaccus. That went into vulgar French (all French is vulgar) as eschec with the plural esches and that went into English as chess. But when the king is crippled, you still say Checkmate.

Chess used to be played on a “chessboard”. Chessboards are kind of useful because you can arrange stuff on them. For example, when Henry II wanted to do his accounts he did them on:

a quadrangular surface about ten feet in length, five in breadth, placed before those who sit around it in the manner of a table, and all around it it has an edge about the height of one's four fingers, lest any thing placed upon it should fall off. There is placed over the top of the exchequer, moreover, a cloth bought at the Easter term, not an ordinary one but a black one marked with stripes, the stripes being distant from each other the space of a foot or the breadth of a hand. In the spaces moreover are counters placed according to their values
  - Dialogus de Scaccario c. 1180

It looked just like a chessboard and Henry II spoke French it was called the Escheker and that's why Alistair Darling is currently the Chancellor of the Exchequer (the S changed to X through confusion and foolishness).

Back in the twelfth century there was a chap called Elias Ostiarius who worked at the exchequer. He made lots of money there, bought an estate and named it after his job. The house passed down to his descendants and then to the D'Awtrey family (who locked up girls), then to the Crokes, the Wooleys, the Thurbanes, the Russells (bear with me here), the Astleys, the Clutterbucks and the Lees who didn't (thankfully) have any children so they gave it to the nation in 1921 as country house for the use of the Prime Minister. And that's why the Chancellor of the Exchequer often stays at Chequers.

But chess doesn't stop there. We are nowhere near the endgame. I shall continue unchecked.

You see when you shout "Check" the game is stopped. At the very least the other player's moves are limited. From this you got check meaning to attack and the idea of somebody or something being held in check. Check meant to stop, as in checks and balances.

Check or cheque began to mean somebody who stopped things going wrong. For example the Clerk of the Cheque mentioned in Pepys' Diaries had to keep a seperate set of accounts for the shipyard. He checked fraud and served a good lunch.

I walked and enquired how all matters and businesses go, and by and by to the Clerk of the Cheque’s house, and there eat some of his good Jamaica brawne

And from that you get the sense of a check as something that stops dishonesty. At a hatcheck you get a check to prove that you're not stealing somebody else's hat. Bank checks (or cheques) were therefore so called because they checked fraud. Dictionaries say this started in 1789 but, browsing idly through my copy of the State Laws of Delaware, I found this statute of 1786:

And people don't pass laws against things until they've been around for a while. The check was changed to cheque in Britain because of the exchequer and then in 1927 they started to  bounce, which only goes to show that Delaware's legislators were pissing in the wind.

And from there you get check off (1839), check up (1889) and Chekhov (1860-1904). And then the Wright Brothers invented the airplane and people would fly around and navigate by distinctive landmarks called check-points. And then WWII broke out and pilots were trained and then given an examination or checkout. Then shops got checkouts and roadblocks became checkpoints and people went to doctors for checkups and stories checked out of hotels and checked in at checkins wearing a checked shirt and all, dear reader, all because of crippled shahs.

(And it's nothing to do with Czechs).

The Inky Fool tries to guess his opponent's plan