These occur in the early endgame).
Example given by Bill Spight, moved here from WhatWasTheHighestMoveNumber (now thickness versus endgame).
In Ishi no Kazoekata (How to Count), Sakata says that simply making plays based on counting territory is not enough. You also have to play thick yose.
Thick yose are plays that aim at aji. Even though they don't look big, later on they make a profit. For instance, if a ko breaks out later, thick yose generate ko threats.
Sakata gives the following example.
Black was Fujisawa Hideyuki, White was Sakata Eio. Black seems to be lagging, and makes a shobute with .
Having made his kikashi on the top, Fujisawa switches to the large yose in the bottom right.
This is a thick yose. Sakata preferred it to
, protecting his territory in the bottom right.
eliminates some black aji in the top and makes
sente. In return, White allows Black to penetrate deeply into his territory in the bottom right.