Help Identify These Asian Stamps

Here are some stamps that I am having trouble identifying. I believe most are Chinese.








Also, how to determine if this is a reprint of Korea #1...

Believe the fourth stamp is a Japanese saving stamp.

(Will confirm later today upon return home.)

Believe the fourth stamp is a Japanese saving stamp.

(Will confirm later today upon return home.)

4 revenue stamp from Japan (transport)
http://eng.ssjp.dk/revenue/railway.html

2 Japanese occupation of Central China

Always endeavour to offer a design type with Chinese stamps, if you have a catalogue.

Stamp 1
Sc# Type A57
686 1946 $300 on 10c surcharge Dr. Sun Yat Sen

Stamp 5 has me stumped
Sc# Type A37
$500 on $30
Could be nth eastn provinces Sc#44 1947
but the top script does not seem to fit.


Stamp 3
Puppet Govt of Nanking
Sc# 9N104 1944 $5 carmine rose

Stamp 6
Guess
North Eastern Provinces
Postage Due
1948 Sc#J7 $10 on 10c surcharge

#5 $500 CNC surcharge on $30, is definitely China, Northeastern provinces, Scott #44. A couple of characters are not well-printed.

Korea #1 looks genuine from here. The check is to make sure it has no crisscross watermark (Scott watermark 312 used on more modern Korean stamps) which would make it a modern reprint. The reprints are all on somewhat thinner brilliant white paper and have rather dull/matte gum besides.