Star Ocean: Till The End Of Time

After the events on Planet Styx, you'll end up in area called Gemity. This area is essentially a collection of mini-games, head to the main plaza and go either to the Northeast or Northwest transporter to access Runic Chess. If you forgot how to play Runic Chess from your time in the Ancient Ruins of Mosel, the rules are as follows:

• Thief beats Symbologist
• Symbologist beats Warrior
• Warrior beats Thief

Pretty simple right? Well it's not as simple when you put it on a chess board. Level S Runic Chess is the highest difficulty, and is selectable from the start with an entry fee of 2,200 Fol. Once you pay the fee you will be brought to a board with enemy pieces on it, and will be prompted to select your pieces and watch the match unfold. While what pieces the CPU has on the board are randomized on each attempt, the solution to each board setup is available in this FAQ. Find your opponent's setup and use the pieces the FAQ tells you in the exact place to guarantee victory. Once you defeat all of your opponent's pieces, the trophy will unlock. (Credit to Shaneth21 for the Runic Chess Guide)