Chinese numerals
The pioneering European player Oskar Korschelt disliked kifus because nineteenth century kifus always used Chinese numerals, which are indeed difficult to read unless one is familiar with them. Numbering in that style continued until 1945, having been popular in the 1930s on the basis of nationalist feeling in Japan. (Hindu-Arabic numerals were also used.) In Japanese Go books, when unoccupied points of the board are mentioned in the commentary, they are usually labelled by hiragana (in iroha order) to this day.