number pun
A system where numbers are used to spell out Japanese words. It is similar to things like the use of 2 for to in English, but more complex.
Numbers may be read as native Japanese (kun'yomi), Sino-Japanese (on'yomi), or as English, and are usually shortened to the first kana. They can also be read as though they had dakuten (゛) or handakuten (゜) added to them if necessary. E.g. the number 8 can be ya (short for yattsu), ha (short for hachi), ba (ha with dakuten) or pa (ha with handakuten).