5) While manufacturers often like to think they have control over, or can predict, how the wood in their pianos will respond to different climates where they may be sent, the reality is that there is much about wood that is still not well understood, even by people who are very experienced with it. Facts and figures about drying wood to certain moisture contents with a target humidity or environment in mind may sound convincing to the lay person, and be fine in theory, but in the real world wood usually has a mind of its own, and tends to behave however it pleases, so it often defies predictions about how it will react to certain environments. For this reason certain vital parts of a piano are expected to, and frequently do, change dimensionally within a certain anticipated range: any piano tuner can attest to the fact that the soundboard crown goes up and down, and tuning pins become tighter or looser in the block due to seasonal humidity changes. Other parts of a (well-built) piano are designed to compensate for dimensional changes, so that any swelling or shrinking of wood components can be contained, allowing the piano to still function normally.  All this has come to be expected, as a result of many years of experience building pianos. To suggest that a piano's wood can be controlled, even with local humidity control devices, or any sort of factory pre-seasoning procedure, so that it does not expand or contract at all, is unrealistic.

6) There are several things about the construction of pianos that tend to mitigate the effects of humidity changes on the wood. The fact that there is a thick polyester or polyurethane finish on most Japanese pianos, that tends to seal the wood off from, or protect it from extreme or sudden humidity changes, and the fact that the piano's soundboard and pinblock are usually also coated with some kind of finish also, both help to keep a piano's wood more dimensionally stable. (It is true that no finish completely seals wood off from humidity changes, but certain finishes can provide substantial insulation.) In addition, much of the wood in a piano is laminated, so that layers of wood overlaid over others help restrict or restrain each other from much dimensional change in the areas that matter. Even a piano's soundboard and pinblock are laminated. All these things may help explain why the "gray market" pianos (ones originally seasoned for, and intended for the Japan market and enviornment) have survived much better here than anticipated.  

The Yamaha rep verified that there were problems with some of the first Yamaha pianos to be imported to the U.S. , due to (according to Yamaha) seasoning problems (i.e. the wood not being dried enough at the factory for our climate), back around 1960. He also indicated, however, that Yamaha went to great lengths and expense to rectify the problems, often going so far as to send factory engineers and personnel out to the problem pianos to ascertain the causes and repair the instruments, ultimately ending up replacing the tuning pins in thousands of instruments. In 1963, the three different seasoning processes were reportedly instituted at the factory. 

[Note: Communications  from Yamaha Corporation of America regarding the "problem" pianos that were first sent to the U.S. in the early 1960's, (when Yamaha began exporting them here) seem to focus on loose tuning pins being the main source of difficulty, and state that most of those pianos sent here suffered loose tuning pins within the first couple of years. Officially this was attributed, by Yamaha, to be due to their engineers being unaware of the level of dryness that existed in the U.S.   Yamaha contends that the dryness was due mainly to indoor conditions: the result of insulated houses, heating and air conditioning drying out the air in which the pianos were kept. Yamaha's expressed concern was that some of the pianos originally intended for the Asian climate (so-called "gray market" piano's exported for resale in the U.S.) might exhibit problems similar to those first brought here in the 60's, before Yamaha's engineers had experience producing pianos for so-called "dry" climates such as ours.

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