What is "war tuba"

alt. An acoustic locator, vaguely resembling a tuba, used (by Japan during the World Wars) to provide early warning of incoming aircraft. n. An acoustic locator, vaguely resembling a tuba, used (by Japan during the World Wars) to provide early warning of incoming aircraft.

The Japanese war tuba (known in Japanese as: 九〇式大空中聴音機, "Type 90 large air sound detector") is a colloquial name sometimes applied to this Imperial Japanese Army acoustic locator due to the visual resemblance to the musical tuba. The name derived from a misidentification, possibly in jest, of a historical pre- WWII (1930s) photograph featuring Japanese Emperor Hirohito ( posthumous name Shōwa) inspecting a trio of acoustic locators with a backdrop of anti-aircraft cannons.