M-69 Incendiary cluster bomb

The M-69 incendiary cluster bomb was used to target Japanese cities during World War II. They were nicknamed 'Tokyo Calling Cards'.

The bomb used napalm as an incendiary filler, improving on earlier designs which used thermite or magnesium fillers that burnt more intensely but were less energy/weight effective and easier to put out. They were used in clusters of 36 as part of M19 'aimable clusters', which opened up at about 900 m ASL.

It was tested against typical German and Japanese residential structures at Japanese Village and German Village, constructed at Dugway Proving Ground, Utah, in 1943. The M-69 was a success in the tests, though it would not ultimately be used in raids on Germany due to different tactics being employed there.

They were employed with great effect against the Japanese in mass fire bombing raids starting in March 1945. In the first ten days of raids with the M-69 and M-47, extensive damage was done to Tokyo, Nagoya, Osaka, and Kobe.