Thank you, perf12. The characters circled reads kitte = "stamp". It is not regarded as an identification point for genuineness AFAIK. In fact, the right side of the first character is actually done rather sloppily; compare with the Matsuda stamp.
Of floortrader's forgeries, the top 2 have corner flowers slightly smaller/shorter than the tablet between; hard to tell, but compare with the Matsuda print. The lower left one is by Spiro, with his typical New South Wales-style cancel used on a lot of his stuff. The imperf one is new to me; different inscription and hexagonal box for the character i, of course.
The addresses on the cover needs more investigation, but some comments from my quick observation ;
- there are too many excessive writings to be considered as to be originally written. However this does not mean that the cover is not genuine; people used to utilize the cover to practice writing thus those excess writings may be simply added afterwards.
- The date written on the cover says March 5th and matches the date stamp.
- No arrival date stamp thus the addressee should be somewhere in Tokyo urban area; still struggling to decipher the address
- the perforation of the stamp seems to be unusually large in diameter; seems to be even larger than MLL perforation and need more investigation.
Stamp, postmarks and cover are perfectly genuine. Yes, the "Mei" of Meiji looks strange/distorted, but was probably damaged/blurred and inserted by hand.
Stamp was pasted to the reverse of a Tokyo city-drop mail (1 sen rate!). However the address within Tokyo is difficult to read. Same for the senders return address.
Sure it is possible to plate the stamp.
Get Ichidas two-volume book as reported above. Vol. 2 is just 1:1 photos of sheets and sheet-reconstructions pasted to cardboard pages. And no, it is not so "expensive" as it was in the past. Some auctions offer boxed copies from estates for around $100. Worth every penny. (Yes, some japanese dealers still have mint copies and claim $300).