I used to play Diplomacy at a friday night games club in the mid 80s. It’s a fun game but it can go on for too long if the ‘diplomacy’ sessions go on for too long. To have a good game requires a fair number of players and some rooms for privacy. The games club was awesome as there were lots of people playing other games, it was easy to get lost for a bit and talk some backstabbing with an ally?
It’s been a long time but from what I recall, you only had 3-5 pieces to start, either land or navy. lots of territories but only some had ‘power points’ or whatever the official term was. Seasons would go by (turns) and at certain times of year you counted the power points you had and that was how many units you would then have.
Winning required having more units supporting a battle then the other side, units rarely got destroyed in battle unlessthey could not retreat, and only 1 unit per territory.
So, you have 1 Brit unit in territory #1 (T1) that wants to move in against a german unit in territory #2 (T2) but you have no other units. You ask your buddy the Russian to support you as he has a unit in T3. He does, you write your orders on a paper, so does he, you both put them in the hat and move off. You write T1 to T2 basically and he writes T3 supports T1 into T2 on his paper. You both go on your merry way to another room, you lose track of your ‘buddy’ the russian who is now talking to the Germany about your attack. So, you now rewrite your orders…, you grab a new paper and write down "These orders supercede the orders of T3 supports T1 into T2, the new orders are T3 supports T2 into T1!! You backstab the brit and help the German, and then you go on your merry way back to the brit!!! And you tell him you are setting up the german by pretending to backstab the brit, you write up new orders and so on and so on, thus the time limit per turn.