宇宙亀の方程式 (Uchū Kame no Hōteishiki)

In the distant reaches of the cosmos, brilliant astronomers and researchers study the mysterious “space turtle,” a celestial being whose movements seem to obey an unknown cosmic equation. Players compete to predict the turtle’s course through logic, intuition, and observation—seeking to uncover the formula that defines the universe’s most enigmatic creature. Uchū Kame no Hōteishiki (The Equation of the Space Turtle) is a two-player trick-taking game where players alternately act as the astronomer and the turtle. Each round, both play a card simultaneously, comparing celestial numbers and symbols to resolve “tricks” that represent the turtle’s motion through space. Over a sequence of ten rounds, players aim to align or disrupt the mysterious formula X + Y = Z, represented by unique equation cards. Observation cards introduce special conditions that can alter outcomes and provide strategic depth. The player who best deduces or manipulates the cosmic relationship emerges victorious.