Usually there are many bones in this part of the sheep, but there is often some meat in the cracks of the bones, and the meat selected from the bones tastes delicious, and people know that eating some mutton in life can also help people supplement some nutrition.

Name source:

Su Shi, a great writer in Song Dynasty, was demoted to Huizhou because of political struggle. The local market is scarce and commodities are scarce, but he kills a sheep every day. Because Su Shi is a prisoner on death row, he dare not compete with local dignitaries for good mutton.

So Su Shi privately told the man who killed the sheep to leave him the backbone of the sheep that no one usually wanted, with a little mutton between these bones. After Su Shi took it home, he cooked the sheep's spine first, then poured it on the bones with wine, added a little salt, baked it with fire, and ate it after the flesh and blood were slightly burnt.