After reading this entire discussion, I have changed my mind on the subject at least twice. Very compelling arguments for all the finer points of this debate. I especially loved Al's insights into maintaining an important collection. Although I love Will's parallels into the art world and all the similarities that would pertain here (such as: assistants to masters not receiving any credit, patrons buying a tree just for the "signature" and prestige associated with owning a tree by so-and-so, etc.) IMO the art of bonsai is not always related to oil paintings in museums. I too was surprised by the diminutive size of the Mona Lisa, but I would be willing to guess that it was precisely the same painting I saw that Will saw, regardless of how many years passed in between. The resins that hold the pigment to the canvas have long forgotten the oil that moved it around. A bonsai would not survive long if locked behind bullet proof glass in an air tight chamber. When I do finally make it to see "Goshin" in person, it will likely not be the same as the day John Naka created it. It will be different, but with the same spirit.
Here is my point of view based on a different analogy. If a canine enthusiast is traveling abroad and discovers an exceptionally fine Standard Poodle, with an excellent pedigree, that has been well cared for and nurtured since infancy, he might negotiate a fair price and bring the dog home. He would then set about to hire an excellent professional handler who would resume the responsibilty of training and careing for the promising dog. An employee at the handler's facility would likely begin grooming and conditioning the coat. On the day of the show, that employee would put the dog in his very best "show trim" (this takes many hours of detailed work and concentration) and the handler would then take the dog around the ring. If the dog wins Best In Show that night the credit (and the prize money, if there is any) would go to the owner, everyone in the hobby/sport would more likely credit the handler and the employee goes home with a pay check. Dogs, like trees, are not static works of art and are therfore judged "on the day". The same dog may not even make the cut at a different show because of condition, or poor presentation. You can see my point here.
If the owner saw something in that tree compelling enough to desire to buy it, brokered a fair price for it, is maintaining it or slightly restyling it, has hired someone or taken it to a workshop, is ultimately responsible for the decisions, well, it's his tree.....for that moment. I think that the history of the trees is part of what makes them so interesting and whenever possible an account of who has done what is great and only can enhance the enjoyment. Perhaps the credit could be listed as follows: Joe Smith's tree, initial design by Master So-and-so, collected ____, imported from____,purchased in_____,etc. Whatever events or influences most contributed to what the tree is today. When a tree is in a competition, it is a competitive sport and most of the players know the stats of their competitors. Usually the folks who thought they should have done better will find "evidence" of collusion or unfairness; the winners hardly ever do. I understand the pride of being the sole creator and owner of a tree (I hope a few that I am working on turn out all right) but if you are a purist bonsai artist who will only have in your collection trees that you have created from scratch and you can't stand the thought of any one else ever changing or taking credit for your handiwork, then I recommend the following plan: Never accept a tree offered as a gift; Never buy a tree you find beautiful or compelling, especially from an artist of any note; Never sell a tree- no matter how much money you are offered for it, and finally: Never give away or donate any of your trees- no matter how charitable or important the collection. Clearly this approach would limit what I think of as the best part of experiencing bonsai within the community and takes some of the joy out of it. Best of luck in competition though.
Forgery wouldn't pay off in the long term and I like the remark earlier that a true artist would never enter someone else's work as their own.