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Half X Gomoku

For a Gomoku variant, X starts with just a slash. Then O can place wherever, and then play alternates as normal.

The slash means “reserved”; it doesn’t count for five-in-a-row but it does stop O.

On a turn, X can either both complete the slash and put in a new “reserved” slash elsewhere, or place a new complete X in an empty square. X can’t have more than one “reserved”.

O plays as normal.

The purpose of the Half X variant of Gomoku is to reduce the start player advantage of this otherwise solved game.

Thinking about this for a while makes me realize that it doesn’t work.

Let’s say there is a forced solution to Gomoku.

In that solution, not every X is part of the winning five-in-a-row. Some are only there as stoppers, others as only threats. Since X can move their “reserved” at any time except the final turn of the game (since they can’t win with it—although they can complete an existing reserved on the final turn, that’s still weaker than normal Gomoku when that square instead would’ve been a full X), they can move it on a turn when they are placing a stopper and then leave it there and be in a pretty much isomorphic state to normal “X-always-wins” Gomoku.