I wanted to bring this up because it seems to contradict the conventional wisdom of dating Seikos we have all come to accept, namely, first number year, second number month.
I have only come across this twice, once in the inside caseback of my Champion 850, and now on another watch I've seen up for sale, both from the '60s.
When the first digit is a letter (month), then the next one has to be the year. So my Champion 850 would be December '63, which would be the correct age.
Any possible explanation? I'd be interested in your feedback.