turn-based game Timekeeping is relevant to many types of games, including video games, tabletop role-playing games, board games, and sports. The passage of time must be handled in a way that players find fair and easy to understand. In many games, this is done u ...

s, permanent brain (also called pondering) is the act of

thinking In their most common sense, the terms thought and thinking refer to cognitive processes that can happen independently of sensory stimulation. Their most paradigmatic forms are judging, reasoning, concept formation, problem solving, and delibe ...

during the opponent's turn.

Chess engines Chess is a board game for two players. It is an abstract strategy game that involves no hidden information and no elements of chance. It is played on a square board consisting of 64 squares arranged in an 8×8 grid. The players, referred to ...

that continue calculating even when it is not their turn to play end up choosing moves that are stronger than if they are barred from calculating on their opponent's turn.

Use with chess programs

The strength of

chess program Chess is a board game for two players. It is an abstract strategy game that involves no hidden information and no elements of chance. It is played on a square board consisting of 64 squares arranged in an 8×8 grid. The players, referred to a ...

s depends very much on the amount of time allocated for calculating. Many chess programs use pondering to improve their strength. Current programs cannot create strategic plans, so a program simply tries to predict the opponent's move and begins to calculate its response. If the opponent's move has been guessed correctly, then the program continues to calculate. If the prediction fails, the program begins a new computation. Pondering is less effective than normal thinking. For example, if the program guesses 25% of the opponent's moves correctly, the use of pondering is on average equivalent to increasing the normal calculating time by a factor of 1.25. In chess games between two computers, pondering makes sense only if the competing chess engines use separate

processors Processor may refer to: Computing Hardware * Processor (computing) ** Central processing unit (CPU), the hardware within a computer that executes a program *** Microprocessor, a central processing unit contained on a single integrated circuit ( ...

core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (laboratory), a highly specialized shared research resource * Core (manufacturing), used in casting and molding * Core (optical fiber ...

s. If they share the same core, the pondering program steals half of the time from the program thinking in the normal way and uses the stolen time less effectively. For this reason, chess

GUI Gui or GUI may refer to: People Surname * Gui (surname), an ancient Chinese surname, ''xing'' * Bernard Gui (1261 or 1262–1331), inquisitor of the Dominican Order * Luigi Gui (1914–2010), Italian politician * Gui Minhai (born 1964), Ch ...

s have an option to turn the permanent brain off.

References

* * {{game-stub Chess terminology Computer chess Thought