Japanese Text Input System With Digits

We discuss a Japanese text input method for mobile phones. Different from the current methods that are based on kana kanji conversion system, our system asks user only to input the sequence of digits that in fact corresponds to the sequence of consonants, and then convert it directly into the final kanji from.After the examination on the number of candidates for a sequence of digits, we explain our method of word estimation based on Hidden Markov Model and describe our implementation. Then we report the results of evaluation by comparing the number of needed keystrokes to input various kinds of actual texts.