This proposal is directly responsive to the NASA NNH18ZDA001N-LCLUC call to address ""Land-Use Transitions in Asia"" and in particular to those “in smallholder agricultural systems"". The research characterizes field size changes extracted from medium and high resolution satellite data and investigates them with social science research methods. Rice growing areas in northeastern Thailand, Red River Delta in Vietnam, and Jiangsu Province in China, which are at different stages of agrarian transition, level of development and have different land tenure regimes, will be considered. The main tasks are to (#1) extract fields from moderate resolution contemporary Landsat-8 and Sentinel-2 data acquired circa 2020, (#2) extract fields from commercial high resolution data acquired circa 2010 and 2020, (#3) extract fields from declassified Corona data acquired circa 1970, (#4) characterize the spatio-temporal distribution of field sizes and their changes, (#5) quantify how biophysical and socioeconomic variables influence field size evolution and the agrarian transition, and (#6) Examine the relationship between field size and crop yield per unit of land. The proposed research is novel, timely and important. Comparison of agrarian transition under different land tenure regimes has not been undertaken before. Forced transition in China and Vietnam may foreshadow transitions in the rest of Asia.