All-in requires an entirely different strategy from standard one-on-one Mornington Crescent. Regrettably often, the winner is the player who can cause the maximum inconvenience to the greatest number of opponents in the shortest possible space of time. However, it is even more often the case that the winner is the person who manages to get their strategy in fastest, without actually breaking the conventions of when to move. In spite of this, it can sometimes be better to hold off and wait for other players to move out of the way first, even if that means allowing another player two, three or even four moves between one's last move and one's next.
Strategy and tactics usually result in an 'every man for himself' approach, but if one player seems to be getting too far ahead the other players will often form brief, unspoken alliances to drag the perceived leader back. Sometimes a leading group will break away, providing a little mutual assistance. Such alliances are always brief, because one player must inevitably backstab the others; only one player can win.
Eamon Ruttsborough was recognised as the greatest master of All-In MC, with 18 wins at the IMCS World Championship's All-In event. Interestingly, no referee ever ruled any move of his illegal for 'moving too often', although he was called for practically everything else (and got away with yet more.) Surprisingly perhaps, Mrs Trellis is next with 13 wins – 12 of them as part of Grand Slams.
Since 1998, a new championship has been set up – the St. Pancras International All-In Mornington Crescent Championships, where nothing is played but All-In MC from dawn till dusk in four sessions punctuated by morning coffee break, lunch and afternoon tea break, for a week. Each time a game ends, another begins, with just a short delay while the token differentials from the previous game are added up. Taking part is a heroic feat of stamina. Players are allowed to 'sit out' a game and join in the next one, and very few play every game in the week (although those who do despise the others as wusses.) Prize money is divided equally between those players who have gained the most wins and those that possess the highest token difference values over the course of the tournament.
The winners of the inaugural tournament were Vic Stannard for the most game wins – to nobody's surprise – and Shiela Ondyszeki for the best token differential. Stannard gained the greater plaudits for his achievement, but Ondyszeki took the most prize money because she had also won fourth prize on the Most Wins list, while Stannard was nowhere near even the top twenty for token difference. Characteristically, Stannard declared the tournament "great fun", while an exhausted Ondyszeki stated she had only entered it as an experiment – "Never again!"