Chinese Overprint Ink?

Top right sorry

That last picture from the Siegel auction is definitely a Kiangsi. The 2 matches the Kiangsi 2 and the upper right matches. You should get a newer catalog. All the characters match. On your stamp the upper part of the 2 is more curved with a ball where the Kiangsi isn't as curved.

Thanks
(obvious again on needing a new reference book)
I don't question the authenticity of the stamp shown
I simply asked for direct comparisons so I could see
(Exactly the same stamps)
Close is the guess I thought I took at the beginning
(little things made me wrong)
But if close enough is considered what it is...
That's that :) I'm learning
Still a penny paper oneway or another
things changed a Lot during the times and slight alterations
Happened all the time
that interests me
I'm just trying to keep learning
Thanks for any help

Taking perf12's image from the Siegal auction as an example of Kiangsi, and placing it next to the op's stamp, I see a difference in the spacing of the bottom line. Specifically, the Kiangsi characters seem much closer to the 2. Also, the 20 of Kiangsi seems much lower than the characters. The 20 of the op's stamp isn't so low. And then, as percyjgp says, the curve of the 2 for Kiangsi doesn't quite match that of the op's stamp. Though similar, the Kiangsi 2 does appear less curved. So, does that drive again toward i20 Kwangsi? Hence, because of the secret mark, to Scott #534 on #411 watermarked? That would make the color deep yellow green, rather than blue green. Color can be difficult to judge from a scan or photo, and I'd like some confirmation of the watermark.

For overprints, I always look at the stamp first. Especially these chinese stamps because there are many varieties, Watermarked, Unwatermarked, secret marks, etc.. Then once I figure out what catalogue # the stamp is then I look at what overprints the stamp can have. And like I said before the numbers tend to be unique to most of the varieties, and then the characters. Keep trying and keep asking ?'s when you get stuck.

Thank you
I appreciate the help
I understand that the pieces are designed by the pawn
So to speak Lol
there systems weren't without thought
The stamp was kinda like a chess board
That's how I'm seeing it

I'll have to get something to check for the watermark
Yes I'm that new lol
Old catalog no fluid clearly don't know what I'm doing
Thanks for being helpful

Ill post pics of watermark check Later
Until I do here's another blast from The past
That my old book doesn't give a clear picture on
Yes I need a new book moving on lol
Dealing with the over print
So I gather the stamps are-
1964 (interesting year)
engraved Perf 14
15-16 a2
Where I get lost is finding the surcharge?
Again yes I need a new catalogue

The underlying stamps are Northeastern Province Republic of China stamps. The overprint is PRC and would be found in the 3L catalog section starting at 3L37. The value is actually written in Chinese as the PRC at the time would never use anything else. The orange 50 looks like it reads 3 Yuan on the right side or as we would right $3, so that lends me to think it is 3L46 based on the upper right character. The one on the left has stumped me, as it is a $40 on 25, but the overprint in the catalog has it in Red. This would put it as 3L49 or 3L64, and based on the characters I am leaning towards 3L49 as there are only 2 characters on the left.

Thanks again
Percyjpg
I did my best to take up close of the two Left characters

Oops missed one

The characters are good. Looking at the catalogue again, and looking at the characters closer. It appears that the top left character is a different version of 1 and the bottom is different version of yuan, so it is $1 on 25. The color of the stamp is black green, and the overprint is green even though it looks black. This make it 3L60. I need to brush up more on my Chinese.

Heavy hinge
No watermark

I see a 3 lol

Or 3 D
Could be hinge mark?