This paper exploits farm-level data of rice cultivating farmers in1935 to examine the farm size-productivity relationship in the Shonai Region of Yamagata Prefecture. We find no clear inverse relationship between farm size and land productivity or input intensity. The farmland rental market was almost perfect for leasing-out, but not for leasing-in. These findings suggest that the inverse relationship did not prevail because the farmland rental market was relatively efficient. However, we did find some evidence that land-scarce farmers were not able to lease-in enough land, and therefore kept excess labor relative to land.