Tac-Tickle Solved: A Minimal Computer-Assisted Proof of a Draw

We report a computer-assisted solution of the specified 4×5 game Tac-Tickle, also known as Nu Tic-Tac-Toe. For simplicity the second occurrence of an identical board and side to move is a draw, exhaustive retrograde analysis classifies all 7,795,903 complete positions reachable from the standard initial position. Its perfect-play value is a draw. A compact certificate reduces the drawing strategy to two recurrent positions, H and K, each closed by a four-ply repetition. Interactive proof explorer: https://tac-tickle-solved.ilyamex.chatgpt.site/ Full proof graph: https://tac-tickle-tree.ilyamex.chatgpt.site/ No claim of novelty or priority over earlier published or unpublished work is made.