http://detectiveconanworld.com/wiki/Talk:Masaaki Okakura#"O.K.A.K.U.R.A. M.A.S.A.A.K.I."
The romaji letters "O.K.A.K.U.R.A. M.A.S.A.A.K.I." in the full name of the Black Organization NOC killer by the serial killer in movie 13 hides a secret message, to anagram and form "Akai k.o. Karasuma", which means "Akai knocks out Karasuma". It's a crucial hint that the FBI agent Shuichi Akai could defeat Renya Karasuma, the Black Organization's boss, whose true identity was still a mystery at the time of the movie's release. Furthermore, it can also be "Oki a.k.a. Karasuma", meaning "Oki alias Karasuma". It could be another hint that Yoko "Oki"no is the boss' current identity, but until the author's revelation it's only a speculation.
