King Tropism is a simplified form of king safety evaluation.

• It takes into account the distance between the King and the attacking pieces, possibly weighted against piece value.
• For example, one may double the distance value for a queen, and halve it for bishops and rooks.
• This kind of evaluation acts in a probabilistic way - it is by no means certain that being close to the king helps in attacking it.

For example, if white castles short, black rook on h8 gets a higher tropism value regardless whether it stands on an open file.

• Nevertheless, using this kind of crude evaluation term increases a probability of building up an attack.

King Tropism