Nagano prefecture is known throughout Japan for its buckwheat, which finds its way into much of the region’s cuisine, from the famed Shinshū soba (more on which here, here, and here) to soba manju (sweet red bean paste wrapped in a thin buckwheat skin) and soba cha, a mellow, caffeine-free tea made from buckwheat kernels. The buckwheat harvest, which takes place in the late fall after October’s rice harvest, is hard and laborious work. Preparing the buckwheat for cooking is no easier: after harvesting, the buckwheat grains are threshed and sorted. Traditionally, stone mills are used to grind the grains into flour. Freshly milled buckwheat flour has the most delicate flavor, and so soba made immediately after the fall harvest is held in high regard.