Age of Yamaha with D before number?

[Corporatefilms123]

What is the age of this U1 piano? Serial number D1744821. I'm confused by the letter before the numbers. On a British website it said the D meant the piano was manufactured in the 60's, and has two pedals, which this particular piano does have. But then it goes on to say that having a 7 digit serial number means it was manufactured in the 1970's. When typing in just the numbers, leaving out the letter, it says the piano was made in 1974.

Thank you to anyone that can help me out with my confusion! I would like to know when this piano was truly manufactured.

[Barrie Heaton]

1740000 = c1973

E is Europe "N" prefix Kemble’s
C is Chinese
J is Indonesia
H Japanese H. X. D. Are a model prefix
"T", the piano was manufactured in Thomaston, Georgia
"U", the piano was manufactured in South Haven, Michigan.


Barrie