Triode_Tokyo-Radio-Co-Ltd

This tube is a very early Japanese type with a brass UV base and no top exhaust tip. It would date from c. 1923 to 1925 and may have a "tubulated seal" exhaust tube from the bottom of the bulb, where the element glass structure is welded to the bulb, rather than the usual type of seal with the exhaust tube at the centre of the bottom of the pinch. This method was used by the Japanese light bulb industry to avoid patent litigation with the General Electric Co (USA). The tube was most likely a detector.

Further information coming from Hiroyuki Kato san:

This tube is also known as TV-7

Tokyo Radio was formed in 1922. The company was absorbed by another company. Tokyo Radio's TV-7 tube was advertised in a magazine in 1924. It received the type certificate from the Ministry of Communication in 1925. 1926 issue of the Radio Yearbook lists the TV-7 as a detector/amplifier and the specifications are as below.

Plate Voltage: 80V
Filament Voltage: 4.5V (Another source says 4.0V)
Filament Current: ~0.7A