As part of a series commemorating the 50th anniversary of the end of World War II, the postal service designed a stamp with a painting of a mushroom cloud captioned “Atomic bombs hasten war’s end, August 1945.”
Perhaps not surprisingly, the Japanese government, peace activists, and many others were offended by a stamp that appeared to celebrate a terrifying weapon that multiple countries now possessed and occasionally threatened to use.
After the intervention of then-President Bill Clinton, postal officials reconsidered the matter and the stamp was never released (although a prototype for it, showing “00” where the stamp’s denomination would have appeared, is easily found online).
In its place, the post office substituted an image of President Harry Truman announcing Japan’s surrender on August 14, 1945. (The stamp in the middle at the bottom of the souvenir sheet below).
– From a discussion of the most controversial stamps in the history of the United States on history.com

I am pulling apart a pile of definitive stamp series from Japan issued from 1913 to 1937 called the Tazawa series, after their designer.

Following the death of Emperor Meiji, the Japanese government held its first-ever open prize competition to select a new standard stamp design.

Tazawa Shōgen was an employee of the Japanese Printing Bureau and won this national contest to design the country’s standard definitive stamps in 1913.

The stamps typically feature the Imperial Chrysanthemum crest, floral motifs, or national coats of arms and were used extensively for domestic and international mail.