Japanese Monster?

A couple of weeks ago I was flicking through an Archive here in the UK. I was mostly after light tank related information. I then saw a file simply called "light tanks". So a file in a UK archive titled "light tanks"... want to guess what it held? Well it did have a few pages on Japanese light tanks,  but it was mostly a file built up by MI10 (the intelligence department for foreign equipment) during the war about what we now know as the Type 97 Chi-Ha.

Inside it gave an interesting look at what an Intelligence Officer has to work with to produce a viable assessment. Including information from a Japanese POW. Now I don't know if this POW, or the later one, was deliberately providing false information, or if they genuinely believed what they were saying.

The first POW was a Lieutenant in the 1st Independent Mixed Regiment on Saipan, he was captured in July 1944. However half his interrogation file seems to be missing, and only the bits relating to the tank survive. He stated that the Type 97 Chi-Ha had 15 mm of armour and a twelve cylinder diesel engine. His unit had trained on them in August 1941.

Equally he claimed all tanks had radio's, air conditioning and twin 47mm guns, with one mounted in the standard turret and another in the hull. He also claimed that they could fit 30 ammunition boxes in the tank, each box being 2 feet long, 1 foot tall and 1.5 feet wide.

The POW's were asked to draw sketches of the tanks.

Finally and most bizarrely he claimed as well as one drive wheel at the front, it had two smaller drive wheels at the back, both 14 inches across. The intelligence officer indicates that this might signify an earlier model.
The POW also gave a rundown of crew numbers. Three men for this particular medium tank, two for a light tank and an unknown number for a heavy tank.
"Heavy tanks?" I thought, so more searching ensued, and another POW report was found.

This one is from a private captured in the Manus Islands. He was wounded and sought help from natives. Unsurprisingly they promised to help and simply turned him over to the US forces some time around the 6th of August 1944. In civilian life he'd been a foreman at the Hitachi's forging plant at Kameari, where he'd been working up until at least November 1943. Whilst there he'd seen several of Japan's heavy tanks; the Type 97.

More guns needed I think...

The Type 97 Heavy was 22 feet long, 8 feet 6" tall and 9 feet wide, weighing in at 27 tons. Protected by 30mm of armour its 300 horsepower engine could move it at 15mph, it could climb a 35 degree slope and had a crew of six.

Then this story takes a bizarre turn. In one of the files I was reading there was a page of French. When translated it was further stats for the Type 97 Heavy Tank. In a final odd twist some original captured Japanese documents appear, again detailing the Type 97, with plans which look somewhat like the above sketch.
Further searching finds even more of what appear to be original Japanese plans for several models of heavy tanks.

Finally, I'll leave you with a report that is a bit of a mystery. What were the Japanese firing? Any of you want to take a swing at it?