[David]

Originally Posted by A. G. Maisey

In respect of the pattern of blade corrosion.

This raises no questions at all with me. The edges of the blade are steel, where this steel is hardened the corrosion pattern will accelerate, what I believe I can see in these edges is a typical pattern.

The body of the blade is iron + nickel, this corrodes much more slowly than heat treated steel, I expect to see a different and much milder corrosion pattern in these areas.

Keris blades are normally only heat treated for a part of the way up the blade, this is a design feature used to prevent breakage, the keris is used to thrust, the cut is secondary, so only the tip of the blade needs to be hardened. In a Javanese blade the furthest up the blade the hardening goes is the tip of the sogokan, or its equivalent position where there is no sogokan; in many areas only the first couple of inches of the blade are hardened.

The blade only I think could originate from Klungkung, Kusamba, pre-puputan.

My guess, I emphasise "guess", is that this is a dealer's montage, very possibly put together in Singapore.

Thanks for your input on the blade. I could not be as sure as you, but it did raise some red flags for me spurring my comment.
I am still confused by the diagonally incised line near the front of the gonjo. Not a feature i can say i have seen on Bali keris. Do you have some experience with seeing this feature before?