I,J, K and M.ġ971-1974: PyMxxxx, where years are based on the Imperial Japanese Calendar (i.e. Also see Kuwahara.įUJI (Japan): P designates assumed production facility codes with known characters including F.G. Identity unknown but since format turns up primarily on Zebfrakenko and Zebra, it may be Kenko.ĭIAMOND BACK (USA): See Fairly, N(1), U(1).ĭODSUN (Taiwan): Insufficient data, but format appears to be DSBM ymmxxxx(x) & DS ym mxxxx(x) based on limited small size.įEDERAL (Indonesia) Insufficient data but starts with FC. Inusffient data to determine if 3rd character is a fortnight or month indicator. The formats are easily confused with Miyata.ĬENTURION (USA): See Fairly, Katakura, Matsu****a, Mikki, N(1), Tano, U(1).ĬENTURION (Germany): see Merida, Java Perdanaĭ(1) (Japan): D yFxxxxx or D yMxxxxx. Grant Peterson, who was designer for Bridgestone starting in the mid-1980s, has stated that the alpha character is a month indicator, however, apparent fortnight indicators a high as "T" have been seen as early as 1973. This number string is typically four to six characters in length but can vary.ĪZUKI (USA): See Kawamura, Kuwahara, Giant. Xxxx indcates a numeric characters designating the sequential frame number within a the fortnight, month or year. Yy indicates two numeric characters designating the last two digits of the year (i.e. With such codes, you have to determine the decade based on frame characteristics, components, etc. Y indicates a numeric character designating the last digit of the year (i.e. Mm indicates two numeric characters designating the month (i.e 01 = January, 02=February. The specific convention will be listed under the manufacturer entry. The year that corresponds to a particular alpha character can vary significantly. Y indicates an alpha character designating the year. M indicates an alpha character designating the month (i.e. Hopefully, it is self-explanatory with the use of the following legend:į indicates an alpha character designating the fortnight (i.e. Anybody having any further data, insight or corrections can contact me via the forum's private message process. The nationality of the brand owner ( pre- 1990) is stated in parentheses. Contract manufactured brands are cross-reference to the manufacturer. The level of confidence in the decryption is high, unless otherwise stated, though it is dynamic and may not be 100% accurate. The guide is not necessarily comprehensive, as it only represents what has been collected and decrypted.
This guide compiles the results of a decade of data collection of pre-1990 Asian serial numbers. Many of you will be aware of my penchant for collecting and analyzing serial numbers.