A question I hear from time to time is: do fakes exist, and how do I know if it's fake?
This is a question that others have answered before - Dan King in his book and also Rich Catalano before he shut down his site on sake cups. Basically - no, this really isn't a corner of the militaria market that has many fakes. The reason is quite simple - it's not worth it.
Consider the average cup - let's say it's about $10 for a good condition cup. To make a fake cup, one has to get a ceramic cup, decorate it with a decorative pattern that looks right, and have it re-fired so that the words stick on the right way. That's not a trivial amount of work. All that work for...$10? Sure, one could indeed try to decorate it with something rarer, something that will be worth more. A tank cup, perhaps, or a kempeitai cup. The fact is though, even then, you're talking about an effort that will yield less than $100 a cup for the most part. For things like lacquer cups, the work involved is even more complicated - carving a piece of wood to make a lacquer cup in the first place, then decorating it, is a lot of work, an art that is now confined to a relatively small number of skilled artisans. If you have enough skill to decorate a lacquer cup nicely in the old style, you can make a very good living selling new stuff under your own name, not faking old military cups that sell for $20 a piece.
The thing is, there's a vast market out there for ceramics. As I've mentioned before, I got into this hobby not from the militaria angle, even though I'm a historian myself. I got interested in these cups as I was looking for antique teaware. Whereas these cups are usually in the single or double digits in cost, an antique tea cup that is well decorated can easily sell for hundreds of dollars. If you're going to fake something, that itself is already a far more profitable area to fake stuff in.
In fact, the military theme is a turnoff for a lot of people. The market for antique ceramics is now mostly driven by mainland Chinese buyers looking to buy up all manners of antique wares - for tea, for wine, for decoration, etc. Of all the decorations you put on a cup, a Japanese military themed one is probably the worst you can think of in terms of elevating buying interest from these buyers - the last thing they'd want to do is to sip tea or wine from a cup that commemorates a Japanese soldier coming home after victory in the China Incident in the 1930s. Yes, it is very interesting for those of us who like this hobby, but that's not where the big market is, and counterfeiters are always drawn to the biggest crowds, not these niche markets with relatively low values.
In other words, this is one of those areas of collecting where you can be relatively safe in knowing that what you buy is indeed a real piece of history from at least 1945 or earlier.
Now, having said all that, fakes do exist and I do see them once in a while. The funniest is one I've seen for the Yamato, a bowl that is supposed to be for officers on the battleship Yamato.
The thing is, the phrase on the bowl literally just says "Used for officers on battleship Yamato" and on the back "Showa 18th year". The bowl looks literally the same as one I bought from Crate & Barrel some years ago and used for a long time, just without the words. That's about the same as having a crude white bowl stamped with the words "used by Erwin Rommel" "1943". Just... no.
There are also the old kamikaze cups, bowls, and bottles that show up once in a while. Here are a few examples:
They are always the same - a stamped image of the Zero, with a phrase that says something like "Showa 19th year" "Kamikaze Special Attack Unit". They're fake. However, even though people know these are fake, I have had customers ask me if I have any of these - because they still look cool. Fact is, the Zero showed up too late in the war to feature on much of anything. I guess some see this as a consolation prize.