That's fascinating about him playing on period instruments. 1859 is very early for a Blüthner - the company was founded in 1853. Mine is a Blüthner from 1935 - at least, that's what the original sales card at the Blüthner showrooms in London has to say. But that card describes a much smaller piano than mine. I suspect that at some point it was restored and the serial numbers printed on the soundboard became confused. I doubt very much that they would have written out an incorrect receipt to a customer.
When I bought mine, I was originally interested in an 1898 instrument at Roberts Pianos in Oxford - that may well have been identical to Debussy's Blüthner because he was only 36 when it was built. It was in a gorgeous rosewood with black, deep red and cream stripes in the grain and I really loved its appearance. But it was the Blüthner patent action, and I found that it was too weak in the second and third octaves above middle C. Blüthner introduced an "aliquot" stringing system, in which the top third of the piano had a 4th string tuned to each note that wasn't struck by the hammer but vibrated in sympathy. I'm not convinced that it makes a lot of difference, but even modern Blüthners have an extra string. The design has changed slightly though. I did play some Debussy on that piano when we tried it in the showroom, and I have never made the 1st Arabesque sing as much as I did that day. The bass strings had an absolutely exquisite tone. But it was frustrating for playing Beethoven because of the weakness of the sound in the upper registers and after about 2 hours playing it I decided, with great sadness, that that piano wasn't for me.
The piano I did buy was still being French polished when we got there and was held up on scaffolding poles as the legs were with the polisher. They put the keyboard back in and I played it and fell in love. It's a gorgeous piano. It's in mahogany and doesn't have the wide range of colours in the wood that the older one did but it is still very attractive. Blüthner abandoned their "patent" action in the mid-1920s and moved over to the same type of action that Bechstein and Steinway were using and mine has the more modern action.
Blüthners are manufactured in Leipzig and Marcus Robert, who sold me mine, reckons that the Communist-era pianos are not so good as the pre-war ones. He says that they are getting much better again now though. I tried out a reasonably modern one - 1980s I think - at an auction at the Conway Hall, and I thought it sounded fine. I didn't like the finish though - the wood had a really thick layer of polyurethane or whatever - so thick that it looked as though it was covered in glass. I have also played new Blüthners at the Baker Street showrooms - two 9' concert grands and a really tall upright. Apparently that model of upright is the tallest piano currently being manufactured by anyone. It had a massive sound, but had the heaviest action of any piano I have ever played. No doubt that could have been adjusted.
I read somewhere that in the 1930s, if Jews who were Blüthner owners decided to emigrate to escape the nazis, the Blüthner company paid for the export of their piano. I don't know how often this happened, but the story I read was that the conductor of the Leipzig and Berlin Radio Orchestra turned up in San Francisco and about 6 months later, to his surprise, so did his Blüthner. IIRC I read this on the blog of a US piano teacher named Mark Polishook, who was working in Leicester. I've looked at the Wiki entries for the conductors of both orchestras but can't find anyone whose biography suggests that it might have been them. I understand that during WW2 the nazis commandeered the Leipzig factory and turned it into a place that manufactured packing cases for munitions.
I must stop now. I have an urge to play Debussy's first arabesque...