Encrypted Diary in Japanese Solved in 4 Hours on Twitter

I wrote about solution (2014) of an encrypted diary (1995-1996) in Japanese posted on twitter in a separate entry in Japanese. The diary belonged to a deceased uncle of the poster. (Hence, the hash tag #叔父日記暗号 (Uncle's Diary Cipher).) The solution was achieved in four hours. The entries of 1995 turned out to be based on Japanese Morse Code. A character is enciphered by interchange of dots and dashes of the Japanese Morse code. In 1996, a simple Caesar cipher was used, but it was based on old Japanese syllabary I-RO-HA.