The designer is unstated on these postcards, which were designed during the mid to late 1970s, but these playful illustrations alongside what looks to be Frankfurter Bold definitely fit the criteria of friendliness and efficiency
Jazz Journal was first published in 1946 by Sinclair Traill, who also had some of his photographs used on the covers. The magazine is now online but remained in print for several decades, as Britain's longest enduring jazz magazine.
The background of Kamekura's mark designs is his boldness in eliminating all the waste, combining simplification derived from Japanese traditional family crests and Western intellectual mechanics of formation with a sharp modern sense of composition.