Gomoku Overline Rules for Five and Six in a Row
Use Gomoku overline rules to judge six connected stones, count across a gap, and find the point to defend in ProjectGAMR’s freestyle game and exact-five play.
Identify the rule before choosing a move
Gomoku overline rules determine what happens when one move joins six or more stones of the same color. The result can change which empty points deserve attention. Before planning a reply, find the rule that your board uses for the longest connected run through the new stone.
ProjectGAMR’s casual freestyle Gomoku version, checked November 3, 2026, has a 15-by-15 board for two players on one device. Lime opens and each turn places one stone on a vacant intersection. A horizontal, vertical, or diagonal line wins as soon as it reaches five or more. Both colors follow that threshold.
Count outward from the proposed intersection
Pick a vacant point and picture your stone there. Along one axis, count the consecutive stones of your color in one direction. Repeat on the opposite side. Add one for the stone you would place. A gap, an opponent stone, or the edge stops that side of the count.
Repeat the count on all four axes. A move can extend a horizontal row while joining a separate diagonal group. Evaluate each run by itself. Counting every nearby stone together would treat an L-shaped cluster as a straight line. A horizontal pair on one side and a diagonal pair on the other are two separate groups.
Close a gap that joins three and two
Use letters A through O for columns and numbers 1 through 15 for rows. Put Lime stones at D8, E8, F8, H8, and I8, leaving G8 vacant. Place Violet’s intervening turns at A1, C1, E1, G1, and I1 to keep the exercise separate from the central row.
Lime can fill G8 and connect D8 through I8. The count is three to the left, two to the right, and one at the new point. ProjectGAMR declares Lime the winner. In Gomocup’s standard category and under the RIF’s international Gomoku rules, this six-stone line by itself leaves play going. Gomocup’s freestyle category counts six as a win.
Compare a gap that produces exactly five
In a separate exercise, put Lime at D8, E8, G8, and H8. Leave C8, F8, and I8 vacant. Now F8 joins two stones on each side, producing an exact run of five from D8 through H8. The resulting line meets both the freestyle threshold and the exact-five requirement.
Check the two outer neighbors before calling a run exact. An additional Lime at I8 would extend the connected row to six after F8 is filled. This difference is easy to miss when the visible opening looks the same and the extra stone sits beyond the group you counted first.
Turn the same count into a defensive check
When defending on a freestyle board, imagine the opponent occupying each threatening gap. A vacant intersection that joins three stones on one side to two on the other is an immediate winning point. Playing your own stone there separates those groups along that axis.
Scan the rest of the board before committing. The opponent may have another winning point on a different axis, or you may have a legal win on the current turn. The gap count identifies one concrete threat. Use it to compare possible moves instead of defending whichever row looks longest at first glance.
Practice the two positions from a fresh board
Choose New game between the exercises. Alternate the practice moves and stop after the result is declared. The labels in this guide are for counting coordinates from the top left. Use the board’s row and column positions to locate each point.
Tournament rulebooks add their own opening and match procedures. When moving between games, verify the format and then use the same local calculation. Count the whole connected run created by a move, check its length against the rule, and use that result to mark the point you must defend.
Keep exploring
Sources & further reading
- ProjectGAMR Gomoku game and casual rules ↗
- Gomocup freestyle and standard tournament rules ↗
- Renju International Federation’s international Gomoku rules ↗
Have a correction? Tell our editorial team.
