The Japanese were not informed about the German research to any degree that I have ever seen. Nor were the Germans aware of Japanese research. They both had very small research programs that were not aimed at producing weapons in the short-term.

In terms of collaboration, there is only one story of interest that I know of. In July 1943 the Japanese requested, as part of a material exchange program, that the Germans give them 1 ton of uranium ore from Czechoslovakia. The Japanese ore sources were very poor so they couldn't even do significant research on the topic. The Germans asked the Japanese why they wanted the ore, which the Japanese weren't expecting. The Japanese lied: they told the Germans they were doing research of it as a chemical catalyst, with no indication that they were interested in fission.

The Germans were not particularly interested in shipping uranium to the Japanese. Aside from its nuclear usages, it had many conventional uses as well — they were using uranium oxide as a coating of artillery barrels and later in rocket warheads. It had become a scarce commodity within Germany despite the fact that they had much more of it than the Japanese. So they stalled, and finally, in late November, agreed to ship the Japanese 100 kg of uranium oxide. This was considerably less than 1 ton, to the Japanese requested the full amount. The Germans then became suspicious about the catalyst cover story, who stalled some more, which angered the Japanese, who in turn admonished the Germans harshly: "What is going on here that you don't want to cooperate?" But the Germans didn't want to tell the Japanese why they were interested in uranium, or why they were suspicious, because that would tip their hand even further.

Finally, they agreed, in early 1944, to send some uranium on two Japanese submarines out of Kiel. One was sunk on the way over, and the other one was damaged but did bring 500 kg of uranium to Japan in late 1944.

In December 1944, the Japanese requested more uranium from Germany. The Germans agreed, in February 1945, to send another 560 kg of uranium oxide to Japan via submarine, this time the German submarine U-234 (whose name is confusing similar to the isotope uranium-235). The U-234 departed in March 1945, with the uranium as well as some other fruits of German technological research, including a jet aircraft and a glide bomb. It was the last German submarine mission to Japan.

However, V-E day occurred prior to it reaching Japan, and its captain instead decided to surrender to the Americans. So its cargo never reached Japan. The uranium was confiscated by the Americans and added to American Manhattan Project resources (although not in time to be processed into fuel for the bombs at Hiroshima and Nagasaki, as is sometimes alleged).

Anyway — it is an interesting story, and perhaps an illuminating one to your question. Neither of these countries were willing to cooperate on nuclear issues, and were even loathe to admit they were looking into nuclear reactions. And in this area where power potentially overlapped, they got extremely territorial and unpleasant one another.

On the U-234, see esp. Joseph M. Scalia, Germany's Last Mission to Japan: The Failed Voyage of U-234 (Annapolis, MD: Naval Institute, 2000), esp. the appendix on the uranium oxide.