I also haven't read the book yet, but am interested to.
JustYS - the point you highlighted also caught my eye, for similar reasons and questions. I don't think it's fair that I ask what Knaud's conclusions and findings are without trying to read the book myself first, so I'll refrain from that, but I hope that the association with Panataran is more than just the keris being of the same kind of style that is depicted at Panataran.
I also wonder whether there is much to be said about the situation that surrounds the gifting of this keris to Knaud the physician. The story as I know is that Knaud treated Paku Alam V's son for an illness, and the keris is apparently PA-V's gift of gratitude to Knaud for his service.
I don't believe Knaud was keris-interested in the same way Groneman was and even if he was I don't know if he had the means (or desire) to question what he was told about a keris. He was also Dutch, which I can only assume meant that he was viewed with some ambivalence by a people and culture who sometimes view even people of related cultures ambivalently, but I don't know how directly relevant this is. Despite being Dutch he apparently was also interested in Javanese mysticism, so had to have been exposed to the idea of a keris having isi and tuah.
With all that in mind, I do find it difficult to believe that this keris is everything that is claimed about it. Yes it was gifted freely with gratitude, but I have often seen this keris described as a pusaka. I don't think pusakas are gifted in this way, and gratitude does not seem to be a factor in determining the next custodian of a pusaka.
If the author referred to notes or correspondences as evidences for their conclusions or speculations, then I wonder if they considered that the concept of a consistent truth or fact is hard to pin down in or irrelevant in Javanese culture and many other Indonesian cultures. I myself have been confronted with what the Western side of my brain sees as deliberate embellishments or interpolations, by people I love and trust in my family and extended family, concerning tosan aji and other related things. It got to the point that I really wondered what the point of being shamelessly lied to was - nothing I was told could have been historically true or consistent.
How can the story about an object that I know be different to the story my sister or my mother knows, despite being told by the same person?
How is it that who we know to be two distinctly different people in history can now be described as the same person?
How can one historical person be buried in several locations, with all grave sites considered to be the real resting place of the person, with no custodians of the burial site disputing the claim of the other?
I know better to now know that I wasn't being lied to, and these people I know are not liars - they just operate in a completely different world to me and that matters in fundamental, sometimes irreconcilable ways.
The word I find that comes closest to this in English is
retcon - a portmanteau of retroactive continuity. Here's a fine definition from the first paragraph of its wikipedia page:
Retroactive continuity, or retcon for short, is a literary device in which established diegetic facts in the plot of a fictional work (those established through the narrative itself) are adjusted, ignored, supplemented, or contradicted by a subsequently published work which recontextualizes or breaks continuity with the former.
It goes on to explain that authors use retcons under the "
assumption that the changes are unimportant to the audience compared to the new story which can be told".
In Western cultures we accept this in film and literature, and even then, sometimes with passionate argument and dispute. We confine it to the world of fiction that we consume for enjoyment. We do not expect to find retcons in real things with real histories because we associate it with incorrectness at best or manipulation and Orwellian-ness at worst.
We know by now that that is not the case in other cultures - certainly not the culture from which the keris came. To gift a legitimately old keris to someone is not a cheapskate's offer, but perhaps its gifters felt that it needed something more than what reality could permit. And as we know, in some cultures reality may not be an obstacle to elevating something to a status more befitting of the situation, the persons involved, or posterity.