What the surviving record can say about Japanese naval radar

Could Imperial Japanese Navy radar have been more advanced than the surviving record suggests?

Possibly in specialized uses, but the evidence does not establish a hidden mature fleet capability, and late-1930s development was slower than Britain's.

Japanese radar may have been applied to roles that receive little attention in familiar accounts. One example describes radar detecting aircraft that were laying mines over bays and helping defenders search for the mines. That specialized use does not establish a mature hidden fleet capability, which should have affected combat performance and attracted Allied electronic listening. The Imperial Japanese Navy's strong night optics can also be mistaken for proof that its radar was equally advanced. Japanese work was real, although its late-1930s development proceeded more slowly than Britain's. Missing records leave room for uncertainty without becoming evidence of a secret breakthrough.