"Sanzen-sekai no karasu wo koroshi, nushi to asane gam shitemitai" (translated as "I'd kill all the crows in the world to sleep with you in the morning") is an old song sung at a red-light district in the mid-1800s by one guest: Takasugi Shinsaku, a central figure of the early Meiji Restoration who lived a turbulent life. The saying means, "When a crow cries, I must leave this place. Even if I must kill crows all over the world, I want to stay with you a little while longer." The song expresses his longing for amorous time to be prolonged for even just a short while.

In the game Sanzen Sekai: I'd kill all the crows in the world to be with you a little longer, now titled Crows Overkill in its newest edition, players roleplay guests in a red-light district. Many birds gather in front of each player. The players must kill or move birds to prevent them from crying. If birds in front of a player cry, that player must leave the red-light district to go home (i.e. drop out of the game). The player who manages to stay in the red-light district for the longest time wins.

In more detail, players attempt to be the last one called away from the red-light district by the cry of crows, warblers, and roosters. The game consists of two decks of cards — birds and shamisen — along with a time board. Each turn follows this sequence:

1. Cards are drawn from both decks. Birds are placed on the table in front of the current player, while shamisen cards go into their hand.
2. Shamisen cards are then played to eliminate birds.
3. A check is made against the time board to see whether the remaining birds cry and the current player is eliminated.

The turns continue until one player remains in the game and is declared the winner.