yi-chou day pillar

Yin wood rests on an earth branch here, and wood is the element that controls earth. So the stem holds the controlling role over the ground beneath it. Yin stems count their twelve stages in reverse, and for 乙 that count begins at 午 and arrives at Decline in 丑.

Three stems are usually listed inside 丑: 己, 癸 and 辛. From 乙 they read as Indirect Wealth, Indirect Resource and Seven Killings, the last being simply the name for metal that controls wood at matching polarity. 三命通會 has 庚 where the other handbooks have 辛, and it describes 丑 as the store of 庚 metal, so its table would yield a different third reading.

This pair shares the 納音 海中金 with 甲子, yet 三命通會 卷一 separates the two sharply. It calls this one 乙丑金，为顽矿, metal as stubborn ore, against the treasure of its neighbor. Ore goes to the smelter, and the next clause sits well with that picture: 喜火及南方日时, pleased by fire and by southern days and hours. The entry also tags the pair 正印, a word that does not match the ten-god arithmetic, since none of the three stems above is Direct Resource to 乙, and the chapter gives no rule for it.