Gomoku
Gomoku, also called "Five in a Row", is an abstract strategy board game. It is traditionally played with Go pieces (black and white stones) on a Go board, using 15×15 of the 19×19 grid intersections. Because pieces are not moved or removed from the board, Gomoku may also be played as a paper-and-pencil game. The game is known in several countries under different names.
Dunhuang Go Manual
The fourth section (像名弟四) discusses the symbolism of the Go board and the symbolic names given to different positions on the board. For example, the author states that "Go stones are round in imitation of the heavens, and the Go board is square in the same way that the earth is; that there are 361 intersections on the board reflects the division of the ecliptic [into 365 days]" (碁子圓以法天，碁局方以類地。碁有三百六十一道，倣周天之道數). The explicit mention here that a Go board has 361 points indicates that the author of the manual was familiar with the standard board with a 19 × 19 grid, and not the earlier 17 × 17 grid board that is attested in archaeological evidence dating back to the late Han Dynasty (206 BCE – 220 CE) and from paintings dating up to the mid 8th century.