There are many other factors to keyword research, including common misspellings (often due to multiple characters per key on a Japanese keyboard), idioms, broken compounds, and dialects. Standard Tokyo Japanese is the writing system of choice.
Input method (PC, mobile, tablet): Whether you use a "qwerty" style keyboard or the miniature keypad on a mobile, an iPad, or an iPhone, you're led to search in different ways by these different keyboards.
Common mistypings caused by keyboard layouts For instance, Japanese can sometimes have as many as three or four different spellings of the same word (because the writer can use different styles of character).
