The number of curves on the road was 48, matching the 48 letters of the ancient Japanese alphabet. Therefore, the tourist guides started to call the slope Iroha-zaka.

The other method uses 1-D cyclostyle matching algorithm to obtain horizontal and erect gray scale projection curves of two list images, then compares with them if its not homology.

Further, by formularizing the two features with functional curves, matching of Chinese characters is transformed into matching of functional curves.