June (pronounced jyu-nay, not like the month) is a physical magazine that ran from the late 70s to the 90s. It's credited for launching the BL genre out of doujinshi conventions and into a more public consciousness. You could consider it the predecessor of BL. It consists mostly of serialized novels with illustrations as well as some short manga, interviews, writing advice, and articles about relevant topics. Personally, I find the illustration style of June particularly memorable.
Interestingly, June had such an impact on the yaoi genre that it has become its own sub-genre. You might hear someone refer to Ori-June・オリJune and they'll specifically be referring to the kind of yaoi found in the 70s and 80s in the very pages of the June magazine. The stories are characterized by having the following traits: set in an exotic location (eg: European boarding school) and homosexuality stemming from a singular trauma. The iconic Ai no Kusabi started as a novel here.
This is my collection of June volumes sourced in person from second-hand stores and off Mercari.
June
小説 June