Treachery’s the way to win at ‘Diplomacy’ – which makes it just like the real thing

Bullying, betrayal, aggression – it may be just a board game, but the family that plays Diplomacy may never look at each other in the same way again, says old hand Sam Kitchener

A month ago, I threatened to divorce my wife if she didn't invade Tyrolia. "Would you and my father please just form an alliance against me," she begged. "It would make my life easier." I am not an idiot. My father-in-law is hopelessly partisan; there is no chance he would betray his daughter for me. Three times, already, we'd agreed mutual non-aggression pacts in the Balkans, and three times he'd gone ahead and tried to invade Serbia.

After his first act of treachery, he took me to one side. It had been a test; now I had proved my reliability, now he knew what sort of man he was dealing with, he was willing to enter into a genuine alliance. It was at this moment I knew that I definitely couldn't trust him. At my wife's urging I nevertheless struck another deal. Mutual non-aggression in the Balkans. "Promise not to invade Serbia?" I asked. "Promise." He invaded Serbia.

Every unhappy family is unhappy in its own way, but mine aren't some modern equivalent of the House of Saxe-Coburg-Gotha, which dominated Europe in the late 19th and early 20th centuries (I'm not sure who would be. The Clintons?). We were just pretending.

Since May, my wife and I have been playing a lot of Diplomacy. This doesn't mean we've become more measured in our dealings with one another; more sensitive to each other's needs. The opposite. Diplomacy is a board game in which players compete to achieve world domination, taking on the role of various countries in the lead-up to the First World War. The board is a map of Europe; each player (England, France, Germany, Austria-Hungary, Italy, Turkey, and Russia) starts off with a certain number of territories, or supply centres, and the winner is the first to expand to 18. It's a game of intrigue and aggression, which has achieved cult status, complete with tournaments, postal games and dedicated webzines. Henry Kissinger apparently used to play it as practise for the real thing and, inverting this, I've started paying more attention to real life diplomatic flashpoints – the negotiations over a Greek bailout, say.

A distinctive feature of the game, as conceived by its creator, Allan B Calhamer – a Harvard educated postman – is that there is no element of chance. Unlike with Risk, there are no dice; an attack succeeds based solely on whether the units attacking a territory outnumber those defending it. Because you are simultaneously trying to expand into other players' territories and defend your own, you need to strike deals with your fellow Great Powers.

This is where the "diplomacy" comes in. Time is set aside before each turn for negotiations, players leaving the room to thrash out an agreement. In which to flatter, bully, chivvy, lie. Moves are then written down, swapped and read out. It's only now that you know whether an ally has kept their word; and at some point someone is going to have to betray someone, or, as experienced players call it, "stab" them.

It's a strange way to have fun. Clausewitz is supposed to have said that war was the continuation of politics by other means; Chinese Premier Zhou Enlai said diplomacy was the continuation of war by other means. Either way, it's pretty stressful. The game is like a combination of chess, Big Brother, and a balloon debate wheeling desperately out of control.

When a school friend first told me about it, I knew straightaway that this was my sort of thing. Aged 13, I persuaded my family to bunker down in a Suffolk cottage for an entire weekend of Diplomacy. I don't know what we were thinking. "You can't just form an alliance with Sam because he's your son," my stepfather warned Mum. "You have to be willing to betray him."

In the second turn, Mum as Germany reneged on a deal with my stepfather's France, to support my English fleet into Brest, knocking him out of the game. My stepfather went quiet, then declared, unprompted, that he was fine, and going for a walk – from which he did not return for another three hours. Approaching the game as if personal relationships outside it don't exist is both impossible and crazy. The same is true of actual diplomacy. Look at how many of the emails Hillary Clinton has had to release dwell on the personalities of foreign leaders. Nick Clegg, according to her confidant Sidney Blumenthal, was hamstrung by inexperience and "inbred arrogance" (one of the most enjoyable subplots is how much Blumenthal hates Clegg. It feels gleefully disproportionate).

A diplomat needs to know who they're dealing with. They also need to know who the people they're dealing with are themselves having to deal with. My friends found that trying to persuade my wife to "stab" me is a lost cause. "You don't have to live with him." (I've roped everyone into playing an online version of the game. Negotiations are conducted over text and email, so the relentless anxiety and paranoia involved can be stretched out over weeks rather than contained in a single session. The platform is called Backstabbr.)

Similarly, forget the result of his recent referendum, the Greek Prime Minister Alexis Tsipras must have known he was on a hiding to nothing negotiating a better deal with Angela Merkel, when German public opinion was so set against it. He had no leverage. Not like when I texted my actor friend Ben that if he didn't keep to the terms of our deal in Central Europe I would out him in this article as a cheat and a liar and a horrible actor. "It feels like we're playing a different game, now," he texted back.

The object of Diplomacy the game is to obliterate your opponents; one hopes that diplomacy itself has evolved slightly beyond that. What the game does make you appreciate are the compromises and concessions necessary in the real life version, something people ought to bear in mind when David Cameron attempts to renegotiate Britain's membership of the EU.

Many of the voices raised against Barack Obama's recent deal with Iran seem to oppose any agreement with Iran on principle. But what I've learned is, you will inevitably have to deal with rogue states, like my father-in-law, and that even success can leave you feeling a little dirty, especially when it involves breaking the terms of a deal you have just blackmailed Ben into honouring, invading his capital in Vienna, and eliminating him from the game. My wife and I plan on leaving it to the professionals, and switching to a less divorce-inducing pastime. Next month, we'll start learning bridge. µ