This is a layout designed to be optimal for typing Pinyin-romanized Chinese. It offers a 0% chance of intra-syllable consecutive finger-repetition. Index fingers go on A and H.
One thing that really surprised me while I was doing frequency analysis research for designing this keyboard is how rare “c” was in Pinyin Chinese. Even after including instances of it before “h” in “ch,” it is somehow still one of the rarest letters in Pinyin Chinese.