During the Jiading era of the Southern Song, Qingruo Ferry on the Chang River was hit by a spring famine.
A stone of emergency rice cost sixteen strings of cash to transport. Yu Bingheng had nothing to offer as collateral, so he set four old measuring scoops outside the grain shop instead.
He had worked in a grain store, could calculate shipping costs, and knew how to repair measuring tools. But he couldn't figure out one thing: grain boats passed right before his eyes, so why couldn't his neighbors buy even a bowl of rice, though they had copper coins in hand?
A copy of A Book on Relieving Famine and Saving the People, passed from hand to hand, gave him a risky path forward: pool the money of small households, borrow a merchant's boat, and buy grain where the harvest was good.
He thought that to weather this spring famine, all he needed was to bring back twenty shi of rice. Then a grain receipt bearing his name was placed before him: they hadn't even seen the rice, yet the books said they had already received seventy-two shi.
The methods written in a book had to be tested in the mud to find out what would work.
From one borrowed grain boat to a network of grain routes linking several counties, Yu Bingheng's goal remained modest: to make sure the people waiting for rice could finally get a bowl of food that was truly theirs.
