Japan Sacred treasures with flat reverse/two screws reverse: when this change occurred?

[JapanX]

Today we know that sacred treasures orders have three types of reverses (with known time coordinates)

Four rivets reverse (1888-1940s/1967/ ?)

[JapanX]

Flat reverse (1944 (?) / 1946/ 1981)

[JapanX]

Two screws reverse (1982?/1983 – 2003)

[JapanX]

The most difficult time period for attribution is the period between 1944 and 1981 during which both types of reverses (four rivets and flat reverse) were in use (simultaneously? successively? flat/ four rivets/flat?). But at least today we know for a fact when flat reverse was replaced by two screws reverse. It happened between May 29, 1981 and April 25, 1983 (actually I think that change took place during 1982, but I don’t have authentic documented group to prove it).

Check this out.

Orders of sacred treasure 4^th Class that was awarded to Daidou Mikio on May 29, 1981.

[JapanX]

[JapanX]

[JapanX]

[JapanX]

[JapanX]

Doc

[JapanX]

[JapanX]

[JapanX]

[JapanX]

And this 4^th class (that we recently saw in the other thread) was awarded on April 25, 1983 to Tauchi Satoshige.

[JapanX]

[JapanX]

Doc

[JapanX]

So how long this two screws construction was in use?

Ten to one that until 2003.

But the maximum time coordinate that we have today is April 1994.

Take a look at this excellent 4^th class that was awarded to Takagi Yoshihiko on April 4, 1994.

[JapanX]

[JapanX]

[JapanX]

[JapanX]

Doc

[JapanX]

[JapanX]

[JapanX]

[JapanX]

What we really need are documented groups from war years and 1946-1981 time period to find out when Mint was using these two reverses (four rivets and flat).

No worry chaps (actually I am more than sure that you won’t )

Slowly but surely we will sort things out

[fukuoka]

Nick, sorry that I misled you with the JE hallmark. I thought it was a 'J' but upon magnification, the hallmark reads DE, which means that this may indeed signify the year of manufacture.