https://qooah.com/2012/07/24/%e5%93%88%e6%97%a5%e6%97%8f%e7%9a%84%e8%bc%b8%e5%85%a5%e6%b3%95%ef%bc%88part-3%ef%bc%89%e3%80%8agoogle-japanese-input%e3%80%8b/