Analysis of information sources in references of the Wikipedia article "가슴골" in Korean language version.
In 1938, strapless and under-wire bras were invented, but neither hit it big until the 1950s, when exaggerated, pointed bras—with cups that bore more resemblance to those from paper-cup dispensers or Brünnhilde's breastplate than to the human body—were also popular.
The new lift and separation evolved into the torpedo shape of the 1940s, which went nuclear with underwire in the 1950s, when the war's end freed metal for domestic use [...] The struggle to buttress what is naturally low-lying has produced its own mythology, like the legend that in the 1940s Howard Hughes used airplane technology to build a better bra for Jane Russell in The Outlaw.
In 1938, strapless and under-wire bras were invented, but neither hit it big until the 1950s, when exaggerated, pointed bras—with cups that bore more resemblance to those from paper-cup dispensers or Brünnhilde's breastplate than to the human body—were also popular.