Oomoyo

Oomoyo describes a player’s attempt to build an expansive territorial framework by coordinating stones across a wide region of the board, usually along multiple sides. Unlike smaller territorial approaches that aim for immediate point gain, Oomoyo seeks long-term control through potential rather than certainty.

This concept is often associated with influence-based strategies and is especially effective when a player has established thick positions and can pressure the opponent into reducing the moyo at a disadvantage. However, the downside of oomoyo is that it can be vulnerable to invasions if not backed by strong supporting stones.

Oomoyo often arises from fuseki patterns that emphasize influence over immediate territory. A player pursuing oomoyo typically sacrifices local stability for large-scale potential. In response, the opponent usually attempts to invade or reduce the moyo before it solidifies into territory.

In the Invading and Defending Moyos section of The Art of Attachments course, Alexander Dinerstein 3p explores strategies for defending and invading large moyos.