I was able to retrieve your photos and what you have is the top of the line Nishiki Professional with some apparent modifications. The tubular wheelset has been rebuilt as wired-on, which was fairly common. Also, the brakes would typically be centre-pull, as opposed to side-pull, and the saddle would not be a leather version.


The first three characters of the serial number appear to be K7E. The year and month indicators are reversed from the format used by Katakua, who typically built the Professional. However, even if we assume this is just a factory error, it would indicate May 1977 and the bicycle appears slightly older. I suspect this was actually built by a sub-contractor who used the Imperial Japanese Calendar and that the frame manufacture date is May 1972. This could be corroborated by examining the back of the crankarms for date codes. I suspect you are going to find 46-x(x) or 47-x codes, where x indicates the month and 46 & 47 are Showa dynasty years corresponding to 1971 and 1972. Please report what you find.