Thinking of bidding on a Yamaha piano. I'm told it was made in 1983 but was kept in an estate where it was barely used and was well maintained. It was then resold to an eminent piano stoe in Manhattan, where it was tuned and polished and untouched until repurchased a year ago. Buyer is now moving and looking to resell. Inside the piano it says Nippon gakki co ltd YUS 3661700. Seller is asking $4,200. Is that a good price?

A YUS was a nice piano but it's starting to get old. How much life is left in it really depends. The rest of the story means nothing next to a tech inspection. Used pricing depends heavily on condition and local factors, but the serial agrees with the seller's stated age but the model and serial were originally sold in Japan, which brings at least part of the story into question.

So this is a so-called "gray" model? Does that mean I might have trouble with the humidity differences? My other choice is a Kawai 501N Institutional.

Maybe, but very often not. I'm not trying to scare you. At this point, the age and condition are what matter. A tech inspection will usually reveal if the pins are loose or if there are concerns about the piano's internals. If there is a problem, someone can blame it on being "gray" or that it was kept too close to a vent for 25 years - same result.

With a budget of $4200, you have additional choices besides the entry-level Kawai.

Keep shopping. If the big Yamaha still stands out to you, have it inspected and then go for it.