It is a very old game played with a Go set.
The object is to get five stones in a row.
The winning move is to get four in a row open at both ends: your opponent can only block one end on his turn, and you claim the other making five in a row. Therefore, a row of three stones open at both ends needs to be blocked so it wont turn into a double-open-ended four.
So a winning move is to create a three-three or four-three or four-four: placing one stone so that it creates two winning moves at once; only one can be blocked.
Go Luck! number of win-game will record in game-center.