Such a mapping would not be feasible, for several reasons. * There are more kana than English letters. You can see that there are numbers paired with kana, key

Such a mapping would not be feasible, for several reasons. * There are more kana than English letters. You can see that there are numbers paired with kana, keys in the bottom-right with two kana, and on this particular keyboard, ヲ (wo) appears to be omitted. * Broadly speaking, each kana represents a pair of sounds: one of ten consonants plus one of five vowels. You will have English consonants with no real Japanese counterpart, and Japanese consonants with fewer than five appropriate English counterparts.