Thickness

Thickness (also called Atsumi or Atsui) is the strategic strength of stones that are well connected, have few weaknesses, and exert influence over the surrounding area. It develops from strong stones, walls, secure connections, and sound shape that leave the opponent few profitable attacking moves. Its value is usually judged by influence and attacking potential rather than by immediate territory.

Thickness supports nearby groups and makes attacks more powerful. It can help build influence, develop a moyo, or allow you to play actively elsewhere. It is not the same as territory: thickness provides strength and influence but does not automatically become points. A wall is a concrete formation that can provide thickness, whereas thickness describes the resulting strategic quality. Thickness may be inefficient when overconcentrated or when there are no useful targets or direction for its influence.