While farming in his Chikuzen village, Yasusada walked through the Kinai and other provinces, the San'yodo, Ise and Kii, to see advanced farming. In the Kinai especially, land use had developed early, fertilizer was used heavily, and double cropping, growing two crops a year, was widespread. Yasusada visited experienced farmers in each place, listened to them, and wrote down their wisdom.
Book 2 describes how to grow the five grains: rice, wheat and barley, foxtail millet, proso millet and soybeans. On rice, it says roughly this:
Rice is the most important of the five grains. First, choosing good seed rice is essential. Soak the seed in salt water, remove the light grains that float, and choose the heavy grains that sink.
Make the seedbed in a paddy with good sun and an easy water supply. Break the soil fine, level it, apply fertilizer and then sow. While the seedlings grow, adjust the depth of the water to protect them from cold and strong sun.
Transplant when the seedlings have grown just right, without missing the time. Before planting, plow the main paddy well and puddle it to level the soil. Plant the seedlings neither too close nor too sparse, at a suitable spacing.
After transplanting, weed the paddy many times and adjust the water. Rather than applying much fertilizer at once, it is better to watch how the rice is growing and apply it in several doses.
In this way Yasusada set down each step of rice growing plainly, so that farmers could actually use it.