Does anybody know what the difference between the U-1H vs U-1E is? I know the YU(X) series is different from the U(X) series, where X=1,2,3,etc...

But I'm struggling to find out what the letter designation post the U-1 means?

Thanks for the help.

The importance of the trailing letter in the U-series model designation varies. Mostly, they refer to a period of several years where the model did not change. Overall, the changes from one model iteration to its subsequent model iteration are fairly minor. Yamaha experts will tend to remember the specific strengths and weaknesses of a particular model, but to the rest of the world, it is a U1. There are some exceptions where a change may be more significant to the overall quality of the piano. For example, a U10Bl, which is grey market and generally good overall piano does have some slights in construction, thinner arms, thinner back posts that most other U1's.

Is the U10BL not a 52" upright made in Indonesia? They are generally nice pianos, but I still prefer a U1.

From my understanding, the series designation means that Yamaha changed some specification of the piano, like case design, scaling, and action possibly. That makes a difference in series a slightly different piano than one of another series. Personally, I like the U1D.

The U10BL is a mostly typical U1 (48", made in Japan in the late 1980's). There is a U1JPE that is a 48" made in Indonesia - is this what you were thinking of?

The U1JPE is a low cost version of the U1, made in Indonesia. However, I do recall a fairly large Yamaha upright piano with the designation "U10BL", so I thought I'd bring it up. On the outside alone, it looked like a U3, but sounded nowhere near as good.

The U10BL is the gray market 48" uprt.that suceeded the U1A in Japan in 1985-1986. The U30BL was the 52" uprt. that succeeded the 52" U3 in the later 80s in Japan.
I suggest one searches the archives in Pianoforum in that I've posted the differences in the scales and vintages of the No.U1,U1D,U1F,U1G,U1H,U1M,U1A,U1E many times over.

Oh well, at least I won't be playing one of those in a long time...