(1)Gunpowder warfare(mines, grenades, cannons and early firearms).

(2)Invention of paper currency

(3)Full-scale scientific progress, bustling commerce and minimal government intervention. Some historians argue that the Song dynasty would've had a industrial revolution if families didn't divide their inheritances equally between siblings, as opposed to England which favors the firstborn heavily in the matter(which would allow concentrated capital to accumulate between generations.)

(4)Invention of movable type printing which makes books shamelessly cheap due to mass production.