When it comes to open conflict, you're at your most vulnerable when you're on the offensive. It's the single insight that unites pursuits as varied as chess and Battlefield 3, and it's true of sumo, too, the ritualised form of warfare from which The Octagon Theory draws most of its inspiration. Theron Daniel Huffman's minimalist iOS offering may look like the younger brother of Geometry Wars and Hard Lines, but beneath the neon vector grids and simulated screen glare lurks a clash of wits with a distinctly classical feel to it, and a game that gives up its secrets slowly, over the course of many defeats.
As with sumo, The Octagon Theory's all about forcing your opponent from the ring, in this case either by knocking his counters from the outer edges of the doughnut-like game board or into the hole in the centre. The winner comes down to whoever has the most pieces left in play once an agreed set of moves have run down.
You shunt a rival's counters around by placing one of your own directly adjacent to it, and you have a decent range of weapons from which to choose. Basic tiles can only push a single enemy, but you are allowed an infinite supply of them and can direct their angle of attack with a swipe of a finger. Other, more advanced, pieces can shove in two or more directions at once, but they're limited in stock – and can often lead to unanticipated consequences. Crucially, it's hard to push tiles over the edge without first getting close to the edge yourself, so victory is generally a matter of minimising your own mistakes as much as exploiting those of your foe.
As with go, another timeless Eastern pursuit, you can place your counters wherever you want on the board, and much of the fun comes from watching the way that the patterns they create shift and ebb over the course of a single game. With a range of nicely differentiated AI personalities to choose from in single-player, a decent local two-player option, and a rule set of unusual elegance and economy, The Octagon Theory leaves you with every reason to work your way towards mastery of this strange, underimagined battlefield. It won't quicken your pulse, but it will steadily rewire your brain; sometimes that's a far superior outcome.