Operation Barclay Board Game is a two-player game of low/medium complexity about the intelligence war between the Allies and their Abwehr counterparts in the Mediterranean theater in 1942-1943.

Operation Barclay puts players in the shoes of competing military intelligence directors who are attempting to mask or learn the truth about the Allied invasion plans for 1943. The Abwehr must attempt to learn where the Allies intend to land next. The London Controlling Section (LCS), the core intelligence agency responsible for Allied intelligence, must prevent the Abwehr from discovering the truth.

The LCS player uses a variable set-up, placing tiles face down to establish where in the Mediterranean a primary and a secondary offensive will occur. Over the course of the six game months, the Abwehr player attempts to win sufficient evidence tokens to be able to turn enough of these tiles face-up to reveal where the Allied offensives will come.

To win evidence tokens, players build hands of five cards to take tricks, similar to poker. While having the best hand will secure two evidence tokens, correctly betting after each player reveals the first three cards of each hand on who will have the best five-card hand is worth three evidence tokens.

Further, players have ways to manipulate the decks from which they draw. They may create a double-cross deck, allowing them to leave cards useful to them face down in a deck to draw from when they choose later — unless the other player takes those cards instead...but perhaps the player who planted those cards was bluffing and hoping the other player would waste their draw on a useless card. Alternatively, players may draw from their own dedicated deck to augment their hands with unique abilities inspired by historical figures, events, and capabilities. The LCS has access to Ultra — decrypts of German codes — but this alone will not be enough if it's not used carefully.