Is it Japanese?
Looks to me like a Soviet 100 mm/56 Model 1934 on naval mount, but I could be wrong.
This is just my first impression, since I’m in a bit of a hurry right now.
Hello, y’all!
Yes, Librarian has unleased his amazing abilities and deciphered my offering! Look out everyone, now there is competition!:o
Sorry, Churchill, I hope I didn’t barge in before you were able to make your offering of a puzzler.:neutral:
Russ
FAA Airman
Proud son of Rose and Wes
Sorry for being late, honorable ladies and gentlemen, but my dear Mother in law was with us again…
Is it Japanese?
Sorry, my dear Herr Major, but the answer is - no.
Looks to me like a Soviet 100 mm/56 Model 1934 on naval mount, but I could be wrong.
Naval mount represents an correct conclusion, but the land of origin and caliber are wrong, my dear Mr. Wingsofwrath. 
Look out everyone, now there is competition!
Oh, please, my dear Mr. Malarz Russ – don’t be so pusillanimous. This is only a game and ability for augmentation of our knowledge about The Queen of Battle – artillery! 
Hahaha, no problems my friend.
Hmm… Is this perchance a 75 mm M/37 Skoda gun?
I am not too sure of the caliber, but it looks very much like the 75 ItK/37 SK anti-aircraft gun…
Bravo, my dear Mr. Wingsofwrath - definitely, it is Škoda. But yet again, caliber and designation are wrong. Nevertheless, you are on the right track!
Heh. I knew the time of my childhood spent amid the guns in the Maritime Museum of Constanta would prove useful someday…
Since there absolutely no chance to measure the caliber in the picture and I lack reference pictures for most of the models produced by Škoda, the only way forward is to slowly work our way trough all of them (luckily there are only 2 probable answers [and several improbable ones])
That being the case, is there even a slight possibility that our mystery contender is a 12 cm/46 Škoda, the type one might find in the Yugoslavian “Beograd” class destroyers?
The other glaring variant would be the 14 cm/56 Škoda, of the Yugoslavian “Dubrovnik”. Is it perchance the latter?
What can I say, my dear Mr. Wingsofwrath? Bravo! Yes, Škoda D 46 M (120 mm) indeed was our misterious artilery piece. Congratulations upon your well-won victory and best wishes for your future sucess!
Please, proceed!
Heartfelt thanks, my dear Mr Librarian!
Before we proceed further, I would like to ask RicemanCDN, as the initiator of this quiz, some clarification for future reference: are we to abide by the posting rules found in the Aircraft thread (only aircraft that saw service in WW2 allowed) or can we follow the more liberal one applied in the AFV topic? (vehicles from different eras are allowed with moderation)
In any case, my next entry is well between the confines of the strictest rules.
Ladies and gentleman, what device fired the following ordnance?
A very specific one called the Holman Projector - a weapon used by the Royal Navy, my dear Mr. Wingsofwrath. Actually, we are observing the High Explosive projectile, which is available here:
http://web.ukonline.co.uk/stephen.johnson/arms/holm10.jpg
Further information about this pretty peculiar weapon are available here:
Well, honorable ladies and gentlemen, finally we were able to find some appropriate photo-materials for this thread:
Naturally, identification of the correct designation will be your standardized task this time as well. Have a good fun! 
76,2mm infantry gun Model 1943, from eEx-Soviet Union of course.
Alas, my dear Mr. Pauk, this piece of ordnance actually possessed another, slightly minor caliber of 75 mm, and was of completely distinct, non-Soviet origin.
BTW – so sorry for my late reply, but I was absolutely overwhelmed with certain professional obligations. :oops:
Bueller? Bueller?
Still stuck on Librarians mystery cannon…
Sorry for my protracted silence, my dear Mr. Malarz Russ. Here is a tiny hint for you – renowned Rheinmetall actually designed this highly intriguing construction.
I think it might be a variant of the 7.5 cm leichtes Infanteriegeschütz 18 .
Either one of the Polish guns that were purchased in 1932 from Germany, or, more likely, since the carriage has an uniquely “Russian” feel, a prototype built during the short lived 1930-33 collaboration between I.P. Uborevich and V.G. Grabin, head Soviet arms manufacturers, with Rheinmetall-Borsig.
You first impression was correct, my dear Mr. Wingsofwrath, Grabin and Co. were not connected with this little piece of artillery.
The only question is: what was the official designation of that tiny cannon? I think that some helpful hints are connected this little video-clip:
http://www.youtube.com/watch?v=d6mOZ0hc9s0&feature=related
And please – don’t hurry. Technical investigations always are serene and unruffled intellectual contemplations.
Taking into account your latest clue, it would appear that the mystery gun is the elusive 1939 7.5 cm le.IG 18F (leichtes Infanteriegeschütz 18 Fallshirmjager) of which only 6 were ever made, a failed paratrooper variant of the aforementioned gun that was superseded in field use by the introduction of the 7.5 cm Leichtgeschütz 40, actually a recoilless rifle using the same ammunition.
The second possibility (and the one towards which I am leaning) is the 7,5 Infanteriegeschütz 37, basically an le.IG 42 tube (unfinished replacement of the IG 18) mounted upon a 3.7cm PAK 35/36 carriage.
Three: 7.5cm leichte Gebirgs Infanteriegeschütze 18 L/11.8 that was also used by the Fallshirmjager.
Actually shown in the picture is the earlier version, with spoked wheels - this weapon never officialy had a gunshield, but who knows…
And, last but not least, a fourth and final variant: 7.5cm Infantriegeschutz L/13, an improved version of the le.IG 18 that saw use in very small numbers.
And that final variant - 7.5cm Infanteriegeschütze L/13 - my dear Mr. Wingsowrath, which was successfully applied in Operation Rösselsprung in former Yugoslavia by the 500th SS-Fallschirmjägerbatallion and two companies of the 1st Fallschirmjäger Division represents the correct answer.
Very good job, my sincerest congratulations. And now – please, proceed. We are awaiting for your next nominee.