Treatise on Armament Technology, Volume 103: Rhymes on Divination — Calculations of the Taiyi Temple, Part 2

original: "武備志" (Wubei Zhi). The "Taiyi" or Grand One refers to a complex system of ancient Chinese divination used to predict large-scale events like wars or natural disasters.

The Verse Says:

The first month is the Snake, the second the Rooster, and the third the Ox.
original: "正巳二雞三月牛" (Zheng Si, er Ji, san yue Niu). These refer to the Earthly Branches: Si, You, and Chou.
The fourth is the Monkey, the fifth the Rat, and the sixth the Dragon’s head.
The seventh is the Pig, the eighth the Rabbit, and the ninth the Goat's position.
In the tenth seek the Tiger, and in the eleventh the Horse.
Only the twelfth month falls upon the Dog.
If you encounter these assigned days, calamities will never cease.

The Judgment Says:

If the army marches on these days, it is certain the soldiers will never return.

Days of Heaven’s Defeat and the Four Exhaustions

The "Four Exhaustions" (Si Qiong) are traditionally considered the final days of each season, representing the point where the seasonal energy is completely spent and therefore unsuitable for starting new ventures.

Spring: Yi-Hai The 12th day of the cycle: Wood and Pig.
Summer: Ding-Hai The 24th day of the cycle: Fire and Pig.
Autumn: Xin-Hai The 48th day of the cycle: Metal and Pig.
Winter: Gui-Hai The 60th and final day of the cycle: Water and Pig.

The Four Seasons: Ren-Zi (Water-Rat), Ding-Mao (Fire-Rabbit), Si-Hai (Snake and Pig).
original: "四季" (Siji). This likely refers to the "Four Separation" or "Four Termination" days that occur at the transition between seasons.