Yamaha M1S, help me, can't find any helpful info about it!

[andnel]

Hello!

Me and my wife just recently purchased a Yamaha M1S serialno D3557395, priced €1000. We think it sounds great, mellow, but a crisp tone. From what i can tell it's made in Japan '82, but other then that I can't find much info about what kind of piano it is and where it belongs in the lineup.

It resembles much of todays B-series but it looks more "sturdy" with curved legs and sounds more mellow than the B-series. Can anyone give me some insights?

Have a great day!

[essence]

It seems to be well regarded from a quick search.