The Japanese in fact tried to purchase a Tiger I tank and the designs to make one. Problem is they couldn't even transport the sample to Japan and it ended up being donated right back to the German Army after Japan paid a hefty sum.

Moreover the real issue was the industrial base. Japan and Italy could have made much larger tanks but they couldn't consistently produce them or keep them working. It is one thing to dream up of a 100 ton tank design. It is an entirely different thing to actually build one. And all that effort of dreaming up a tank and building it completely pales in comparison to the effort required to keep it running.

For reference, the Tiger I tank was so maintenance-intensive that it had to be kept in separate independent battalions with their own logistics trains of 130 trucks and dozens of assorted repair vehicles (see Wolfgang Schneider's "Tigers in Combat"). By contrast a US Army Sherman battalion had a logistical tail of only 30 trucks. When one considers that a Tiger battalion had only 45 tanks compared to the Sherman battalion's 60, then one can see that the running cost of a Tiger was more than four times that of the Sherman based on the number of support vehicles alone! And we haven't even taken into account fuel and spare parts costs.

To further illustrate: There were actually some monstrous Japanese tank designs such as the O-I which were proposed to the military and would have weighed more than 100 tons. None saw action and it's doubtful any even got past the prototype phase (as is claimed by some dubious sources). They were simply too big and beyond Japan's ability to build and maintain.

Finally, and most importantly, the value of armor thickness and gunpower were vastly overrated. US Marines in fact valued the M3 Stuart in many of their Pacific battles more than any other tank because it was more mobile in jungle terrain. A tank doesn't need to have the best armor or gunpower to be an effective tank - the vast majority of engagements fought by tanks were against infantry. And even in the rare tank vs tank battle the tank which scored the first hit often won regardless of gunpower or armor value - Allied studies consistently showed that more than 70% of hits were to the side and rear, hence most tanks were in fact disabled after the first shot regardless of how thick their front armor was.

In 1943 Fiat-Ansaldo were granted a licence to produce Panther tanks but with the Italian surrender it came to nothing.
Source here: http://www-d0.fnal.gov/~turcot/Armour/pz4.htm

I'm sure I read somewhere that the Hungarians wanted to build German tanks but the makers wanted a ridiculous amount for the licence. Does anybody have any more information on this?

Japan tried.

"The Japanese government bought two Panzer IIIs from their German allies during the war (one 50 mm and one 75 mm). Purportedly this was for reverse engineering purposes, since Japan put more emphasis on the development of new military aircraft and naval technology and had been dependent on European influence in designing new tanks. By the time the vehicles were delivered, the Panzer III's technology was obsolete."

• Zaloga, Steven J. (2007). Japanese Tanks 1939–45. Oxford: Osprey. p. 17. ISBN 1-84603-091-9.

I have a better answer than most. The big hold ups for Germany to share tank technology were cost and the distance between the countries. Japan, initially felt heavy tanks were not important to its island and southeast Asia invasion plans. Light tanks served their purpose and aviation (fighter bombers) were their primary shock weapon for ground assaults. Japan also had no intention in attacking Russia until Moscow had fallen, a fact uncovered by the Russians which made them confident when shifting Siberian divisions to halt the Nazi onslaught.

In 1943, Japan worried about American landings and requested information on heavy tanks. Germany sent Japan two packages of technical documentation, and Japan wanted to purchase the tank. However, the cost to produce a Tiger was around 300,000 Reichsmarks in 1943, while the Ministry of Armaments and the Henschel Company requested 645,000 Reichsmarks from the Japanese for a fully loaded tank. The Germans had not simply decided to “cash in” on oversea allies: the cost of technical documentation was also included into the amount; and the tank would be supplied with ammunition, an excellent radio, and optics. Also, Germany was prepared to disassemble and pack the thirty-ton tank for shipment by submarine to Japan.

In 1944, a lease for the tiger was authorized, but shipping it to Japan proved difficult. In June and July, the Allied landings at Normandy cut off German submarine bases at Bordeaux that were the only viable port for shipping the tank.

Sources: • “Tiger Heavy Tank. Lethal Weapon of the Reich” by Mikhail Baryatinskiy • Germany’s Tiger Tanks. Thomas L. Jentz, Hilary L. Doyle

http://imgur.com/sdU9jH6

There was a belated attempt to transfer technology: See: http://www.h-net.org/reviews/showrev.php?id=4048

"U-234 departed Kiel on its maiden voyage on 25 March 1945, bound for Kristiansand, Norway. There it loaded important cargo and personnel and departed on 15 April for a submerged voyage which was to take them around the Cape of Good Hope, eventually concluding in Japan. That transit was never completed.

Among the three hundred ton cargo was three complete Messerschmitt aircraft, a Henschel HS-293 glider-bomb, extra Junkers jet engines, and ten canisters containing 560 kg (1,235 lbs.) of uranium oxide (U235). The uranium oxide was to be used by the Japanese as a catalyst for the production of synthetic methanol used for aviation fuel. Other cargo consisted of one ton of diplomatic mail and 6,615 pounds of technical material including drawings of ME 163 and ME 262 aircraft, plans for the building of aircraft factories, V-1 and V-2 weapons, naval ships (destroyers of classes 36C and Z51, and M and S boats), and submarines (Types II, VII, IX, X, XI, XXI, and XXIII). German fire-control computers, Lorenz 7H2 bombsights, Lufte 7D bombsight computers, FUG 200 Hohehtweil airborne radars and bomb fuses were also included in the manifest along with other military equipment and personal luggage.

Previous examinations of the voyage of U-234 have centered on the cargo carried by the vessel. The presence of the uranium oxide, for example, has generated much interest and conjecture. Scalia, however, shifts this focus, and argues that the submarine's greatest value lay not in her cargo, but in the individuals who were accompanying the material to Japan.

The twelve passengers included a German general and his staff, four German naval officers, civilian engineers and scientists, and two Japanese naval officers. The latter were Lt. Cdr. Tomanaga Hideo, a naval aviator and submarine specialist who had come to Germany by Japanese submarine I-29 in 1943, and Lt. Shoji Genzo, an aircraft specialist and former naval attach in several European countries."

Source: Joseph M. Scalia. Germany's Last Mission to Japan: The Failed Voyage of U-234. Annapolis: Naval Institute Press, 2000. xxiv + 296 pp. $29.95 (cloth), ISBN 978-1-55750-811-9.

Hiya folks!

Unfortunately, as this thread rolls over into the American morning and garners more attention, we're seeing increasing numbers of poor quality responses. This unfortunately extends to many non-top-level responses, where a great number of comments have rapidly wandered off-topic into discussions, comparisons and anecdotes about various WWII tanks. Please keep in mind that the point of this thread is to address OP's question: mentioning something you may have heard about Shermans once is not helpful. spitballing a response based on what you remember from X number of years ago or that one person you talked to once is not helpful.

Proper comments for this subreddit should be in-depth, comprehensive, and informative while properly situating the answer in its historical context. It should also be backed by appropriate primary and secondary sources, whether or not explicitly mentioned in the comment (i.e. you should always be ready to provide sources if asked). In other words, answers here should be such as an historian of the subject would give. Having seen Fury doesn't equip you to answer this question, and neither does your 54% win-rate in World of Tanks.^1

Thanks!

^^^1 ^^^And ^^^I'm ^^^a ^^^56-percenter ^^^anyway ^^^so ^^^take ^^^that. ^^^:P

Please forgive this US ignoramus but;

Its no so simple to share designs as it would seem to be. There is a lot more national and cultural influence in weapons systems than you might expect. The US and Britain supplied tanks to Russia, who used them and liked some aspects of them, but never changed their tank designs. The US examined Russia's T34, but did not like it at all. Why? Because it didn't reflect how we thought tanks should be used. England used the M4, but they didn't use it like the Americans and after the war their tanks didn't look much like M4s. They were the natural revolutions of their own designs. Why? Because their tanks fit their needs, the way they saw the best use of tanks.