Hako Onna is a board game with a theme of Japanese horror. One player takes the role of Hako Onna, a ghost girl who lurks in a box in the mansion, and the others are visitors of the mansion. ("Hako Onna" in English would be "lurking girl" or '"woman in a box"). Visitors win the game if one of the three victory conditions are met: escaping from the mansion, dispelling the girl, or defeating her. However, to fulfil any of them, you must open boxes scattered in the mansion to obtain key items, and when they see her in a box, they are turned into a servant and have to work for her.

The game is reverse hide-and-seek, one-against-all exploration game. During most of Hako Onna's turn, the human players must keep their eyes closed so they cannot see where she moves to or what action she has done. There is also a dexterity element to the gameplay. Before a human player can take their turn, each human player needs to stack a small disc on top the previous ones; if the tower collapses, they've made noise and it instantly becomes Hako Onna's turn.

Hako Onna can win the game in two ways:
If all visitors are turned into servants, or
If she collects all her power.
The human players can win in one of three ways:
If they manage to kill Hako Onna after finding her only weakness,
If they find the secret exit, have the keyring hidden inside the safe, and successfully guess the combination to open it, or
If they can bring peace to Hako Onna by bringing the remains of her body next to her precious doll Mary.
Since its original publication, Hako Onna has reached its third edition. The designer has made small changes to the components and rules, and the box size has changed as a result.