Chisanbop or chisenbop (from Korean chi (ji) finger + sanpŏp (sanbeop) calculation 지산법/指算法) is an abacus-like finger counting method used to perform basic mathematical operations. According to The Complete Book of Chisanbop by Hang Young Pai, chisanbop was created in the 1940s in Korea by Sung Jin Pai and revised by his son Hang Young Pai. He then brought the system to the United States c. 1977. With this method it is possible to display all numbers from 0 to 99 with two hands.