1. To find out the most suitable size of the farmhorse fit for Japanese farm conditions, the workinrzpower of horses, weighing ca. 200, 300, 400, and500 kg. respectively, is planned to be tested. As theone of 200 kg's body weight, Korean ponies, bornin Quelpart Island, were used.2. Test animals were 3, e. g. a stallion and twomares of 190 kg in mean body weight and 113 cmin mean body height. They were not under goodconditions, owing to the shortage of fodders, andhave not ever been trained until they were used in experiments.Endurance, several kinds of practical workingpower and maximum pulling power were tested.Endurance test was made by making animals drawcatrs 3 days successively. Practical working powerswere examined by ploughing, drawing carts, packing, and riding for about 4 hours. Maximum pullingpower was measured by the test of drawing cartsand wagons for a distance of 600 m.3. Results of the endurance test are as follows:Korean ponies can draw carts (self weight: 147 kgand load: about 210 kg) 24 km per day for 3 dayssuccessively. In this test, mean draft resistancewas 20 kg (1/9 of body weight) and working timeper day was about 7 hours (including 2 hours ofrest time). Fatigue seemed to recover almost ineach next morning. Daily work was 480, 000 kg inand calculated horse power was ab out 0.25.In drawing carts (self weight: 14.7 kg and load:480-520 kg) which told 40 kg mean draft resistance, test ponies can draw 8 km per day and worlingtime was about 3 hours (including 1 hour of resttime) per day.4. Results of the test of some practical workingpowers are as follows:(Ploughing)Korean ponies can plough about 720 m2 rice field in about 3 hours and a half. In this test ploughing depth was about 11 cm and mean draft restance was 42-45 kg.(Drawing catrs)Korean ponies can draw carts which told 20 kgmean draft resistance about 13 km for 4 hours(including 1 hour of rest time).(Packing)Korean ponies can load 80 kg and walk 16 kmfor about 4 hours (including half an hour resttime).(Riding)In riding in proporti on of 10 minutes walk and5 minutes trot, Korean ponies can go about 18 kmfor about 4 hours (including 1 hour of rest time).Mean speed per-minute is 74 m in walk and 162 min trot.5. Results of the test of maximum pulling powerare as follows: Tn drawing carts (self weight: 147kg), Korean ponies can draft the load weighingabout 1, 000 kg. In this case, mean draft resistancewas 58-64 kg.In drawing, wagons, test ponies can draft the loadof 675-850 kg, showing 5.6-66 kg of mean draftresistance.6. From the above results, it seems that thereare some suitable farm works for these ponies innese small farms.