The descriptions in this chapter of how a ri (hamlet) or sei (well brigade) is subdivided, governed and taxed are based on Chinese law, originating during the Zhou Dynasty (9th century BC to 256 BC).

According to modern definitions, 1 畝(bou) = 30 坪(tsubo), or 30 x 3.31 = 99.3 square meters. 1 are = 100 square meters (or yards). Based on Youko's 135 cm number, the math doesn't work out as neatly as I would like. But as Enho explains, the length of 1 歩(pu) is relative to a man's stride, so the metric equivalents are close enough (one meter = one yard).

1 跿(ki) = 1 stride
2 跿(ki) = 1 歩(pu) "pace" = 135 cm (according to Youko's calculation), but I'll call it one meter (yard) for the sake of simplicity
1 里(ri) = 300 歩(pu) paces

Note that ri can mean a measure of linear distance, a measure of area, or a "hamlet," all depending on context. Essentially, "hamlet" (里) is used in a political context and "well brigade" (井) in an agricultural context; ri (area or distance) is a geographical definition.

1 畝(bou) = 100 square meters = 1 are (about half a singles tennis court)
1 夫(pu) = 100 畝(bou) = 100 are = 1 hectare = 10,000 歩(pu) square paces
1 夫(pu) = 1 allotment (two American football fields, or a little less than one soccer field)

9 夫(pu) = 1 square 里(ri) = 900 畝(bou) = 90,000 square paces
9 夫(pu) = 1 井(sei) = 1 well brigade or 1 hamlet
3 hamlets = 1 village

According to modern definitions, 1 寸(sun) = 3 cm. However, the way Enho describes it, the width of a finger, 1 寸(sun) is closer to 1 cm. Similarly, 1 升(shou) = 1.8 liters, but described as the amount of liquid you could scoop up with your cupped hands, it's probably more like half a liter or a pint.

1 寸(sun) =1 cm
1 尺(shaku) = 10 寸(sun)
1 丈(jou) = the height of an average man

公田　[こうでん]　kouden, publically administered land on the commons, the yield of which becomes the tax obligation of the ri.
廬家　[ろけ]　roke, privately held land on the commons
井田法　[せいでんほう]　seidenhou, lit. "well and paddy law"

In Japan, real estate listings for houses and apartments include the letters LDK (or just DK). The letters stand for Living room, Dining room, Kitchen, often combined into a single room. The number preceding LDK is the number of bedrooms, so a 2LDK has 2 bedrooms, a living room, dining room, and a kitchen area. What makes this passage particularly funny is that, of course, it isn't Japanese at all, but English (though a usage unique to Japanese).

The graphic is the blueprint of a Japanese apartment. The number following LDK is the floor area measured in jou (帖 or 畳), or tatami mats (85 cm x 179 cm or 3 by 6 feet). The kanji 和 stands for 和室 (washitsu) or "Japanese-style room," meaning that it has tatami mat floor. The rectangles represent the layout of the mats. A 洋室 (youshitsu) is a "western-style room," meaning it has a hardwood floor.