Abstract In view of the increasing importance of uplands as the place for new reclamation throughout monsoon Asia, methods to evaluate different aspects of upland soil capabilities are urgently needed. The methods should aim at quantitative evaluation and practical applicability. The samples to be used in this series of studies were collected from upland fields under cultiVated crops and grasses. They include both vo1canogenous soils (mainly ando soils) and non-vo1canogenous soils (regosols, pseudogleys, acid brown soils, red and yellow soils, etc.). In the present paper available water retention capacity (AWC) of a soil was predicted both from the routine laboratory data and from the characters observed in the field. First, the multiple regression of AWC on such routine laboratory data as bulk density (BD), humus, CEC and textural separates (CS, FS, TS, Silt, Clay) was studied for the entire set of samples. BD showed by far the highest contribution to AWC. Humus, CEC, and total sand (TS) made slight cont...