Ninuki-renjuis a board game created in 1978 by Gary Gabrel. It is a slight simplification of the Japanese game of ninuki-renju, a variant of gomoku played on a Go board of 19 x 19 intersections with white and black stones. The players alternate in placing stones of their color on free intersections; White begins. The players aim to create five vertically, horizontally or diagonally connected stones of their color. If two connected stones of the opponent are surrounded at both sides by a stone of the player's color as a result of that player's move, then that pair of stones is removed from the board. The player who first creates five connected stones or captures five of the opponent's pairs wins.


A sample Ninuki-renju game

The game eventually caught on as an alternative to Ninuki renju and other games in nightclubs, and soon after department stores began selling Ninuki-renju. Games Magazine voted Ninuki-renju to be one of only 20 select "Hall of Fame" winners in 1991. At one time there were Ninuki-renju leagues and clubs around the world; international tournaments were held for a number of years.

In 1983, the then world champion, Rollie Tesh, proposed rule changes for balanced play. He claimed that under the current rules, White could always win with correct play, regardless of Black's plays. His variation of the original rules is called Keryo-Ninuki-renju.

Hasbro ceased distribution of Ninuki-renju in 1993. It later licensed Ninuki-renju to Winning Moves, a classic games publisher, which resurrected the game in 2004. Ninuki-renju is currently available in stores, and directly from Winning Moves.

Ninuki-renju is a registered trademark of Hasbro for strategy game equipment. The community has apparently not found a generic term that applies only to games with these rules.

Ninuki-renju (πέντε) is the number 5 in Greek.

Ninuki-renju was invented while Gabrel was working as a dishwasher at The Hideaway pizzeria in Stillwater, Oklahoma. Now, based on the success of the Ninuki-renju game, Gabrel is the head of a group of Hideaway employees who have opened new Hideaway locations in Tulsa and Oklahoma City. During the early 80s, an all-glass board was made available through the manufactury in Indiana as a limited edition. Glass-board Ninuki-renju sets are now difficult to find.


Strategy
According to official Ninuki-renju instructions, when players have formed a "tessera," or four stones in a row, with two open, adjacent intersections, they have "almost won the game."