They would know, of course, that the traditional three-by-three game always ends in a draw if the players know what they are doing. (Unlike the opponent of the little girl in the picture, who has already gone fatally wrong. She has only to put her Nought in the centre now, and she will win in a couple more moves). Our alients might also have discovered - if their gravity is strong enough to support the game at all - that Connect- 4 (in which pieces must drop to the lowest available point in vertical lines on a seven-by-seven grid) is a win for the player who goes first. (Though it took a good computer program to find the strategy leading by force to a winning line of four in a row.) But where would our alien friends stand on the game of five-in-a-row, also known as Go-Moku or, in its more refined form, Renju?
In its casual form, the game is played on sheets of graph paper, just like an extended game of noughts-and-crosses, and the winner is the first to make five in a row. There is some evidence that such a game existed in China around 4,000 years ago, though the Ancient Greeks and pre-Columbian Americans seems also to have discovered it independently.
The game took a more formal shape around 700AD, when it began to be played in Japan with black and white stones on a Go board. It was not until towards the end of the 19th century, however, that books began to appear on the theory of the game. At around the same time, a general suspicion appeared to emerge that the player who moved first had too much of an advantage. More recently, thanks to the availability of computer analysis, it has been proved that there is a forced win for the player who starts, and that is where the history of the game becomes most interesting.
There are two options when you discover that a popular and challenging game has a basic fault: you can throw it away, or you can change the rules. Most of the world - including Britain - seems to have opted for the former solution. Five-in-a-row is still played here by school-children who have moved beyond old-fashioned noughts-and-crosses, but no form of it ever seems to have been taken seriously enough for formal competitions to have been instigated.
In Japan and some other countries, however, they repaired the game well enough for it to take its place alongside the traditional boardgames of Go and Shogi (Japanese chess). The rule-changes were made in 1899, when the name of the formal game was changed to Renju - which means "string of five pearls" in Japanese.
The new rules form a set of restrictions on types of move that the players are allowed to make. For example, the simplest way to ensure that you will form a line of five in a row is to form a row of four, open at both ends: -0000-. Your opponent cannot block both threats simultaneously. And the simplest way to ensure that you will be able to form such a row of four is to form two distinct open-ended rows of three (in different directions) with a single move. The new rules specified a 15 by 15 board and banned such "double-three" formations. They also banned "double-fours" and "overlines" (lines of more than five in a row), and anyone making such a formation would lose the game instantly. This introduced a new possibility to win a game by creating a threat that could only be met by making one of the proscribed patterns.
The new game of Renju was rapidly seen as more than just a repair of the traditional Go-moku. It was a game of strategy in its own right. And its champions quickly became respected alongside those of other traditional Japanese board games. In the novel "The Master of Go" by Yasunari Kawabata (available in the Penguin Modern Classics series) there is an account of an exclusive gathering at the opening ceremony of the 1938 world Go championship match: "All told, four masters were in the assembly: on Shusai's left, Sekine, thirteenth in the line of Grand Masters of Shogi, as well as Kimura, Master of Shogi, and Takagi, Master of Renju, all brough together for this, the commencement of the Master's last match."
The game, however, has been slow to spread beyond Japan. The International Renju Federation was formed in 1988 and international tournaments are now held in Japan, Sweden, Armenia, Azerbaijan, Latvia and Russia. According to the current rating list, the world's top twenty players include 12 Japanese, four Russians, two Latvians and two Estonians.
But why has Renju never become popular in England? Surely it is just the sort of game to appeal to our large population of game-players. I suspect the answer is as simple as the game itself. One can get away with playing bridge because it is a team game and therefore ostensibly sociable. Backgammon and poker players are admired for their ability to gamble without flinching. One can now (thanks to the efforts of Nigel Short) describe oneself as a chessplayer without inviting looks of pity. But Renju? Deep down, games players like to be taken seriously. Noughts and crosses is a step far.