Japanese mathematics, namely Wasan, was well-developed before the Meiji period. Seki Takakazu (1642?-1708) is the most famous one. Taking Seki's interpolation as an example, the similarities and differences are made between Wasan and Chinese mathematics. According to investigating the sources and attitudes to this problem which both Japanese and Chinese mathematicians dealt with, the paper tries to show how and why Japanese mathematicians accepted Chinese tradition and beyond. Professor Wu Wentsun says that, in the whole history of mathematics, there exist two different major trends which occupy the main stream alternately. The axiomatic deductive system of logic is the one which we are familiar with. Another, he believes, goes to the mechanical algorithm system of program. The latter featured traditional Chinese mathematics, as well as Wasan. As a typical sample of the succession of Chinese tradition, Wasan will help people to understand the real meaning of the mechanical algorithm system of program deeper.