Pearls and Plans at Sea

In the third year of the Yuanzhao era of Great Qian, Lin Xiaowan, an orphan who has just had her engagement broken off, wakes in a leaky thatched hut with a string of sandalwood abacus beads in her palm that can bite.

"Can my fate suppress the Star of Emptiness?" She grips her appointment as a woman household head and smiles coldly. Using the Pythagorean theorem, she measures the powerful families' illegally seized fields; with probability theory, she cuts off unscrupulous merchants' grain routes. While the court argues heatedly over the ancestral rule that "women cannot do mathematics," she is already leading three thousand peasant women through difference equations among the waves of wheat, turning ink dots on the tax ledgers into life-saving millet.

The Nine Chapters on the Mathematical Art System awakens in her blood:

Measure one mu of land, and the abacus beads burn her fingertips red.

Settle a hundred shi of grain, and sandalwood incense forms celestial patterns.

If she dares miscalculate a single account affecting people's livelihoods, a lock of white hair will drift from her temples.

The jade tablet of Vice Minister Cui clashes with her abacus in the Golden Hall. "Headwoman Lin, do you know that no calculation of heaven or earth can measure the human heart?"

She flicks her jadeite hairpin, and the city's locust blossoms suddenly hang like lines of latitude and longitude. "Then let the people calculate it for themselves, from today's land taxes to the fate of the nation a hundred years from now!"