I continue to figure out what to cover on this site with a complete dearth of Supergirl material to bolster new input.
I sometimes am amazed at issues I haven't covered on this site despite this place being around for 12 years. One of those issues is Superman #123, the first appearance of a version of Supergirl. Here we met Super-Girl (notice the hyphen).
It has always been said that this issue was a sort of trial run for Kara. But I wish some of the folks responsible were alive to discuss this more.
Was there a discussion where it was said 'we should make a Supergirl but before we bring one into the universe, let's give a dry run to see how people like it'. Was there a discussion where they said 'if there is a big response we should consider making a Supergirl'? Or did they simply read the responses to this one-off character and say 'we should create one'? I know these are minor differences but I wish I could pick the brains of the creators to see if they remembered. This issue was released in June of 1958. Action Comics #252 came out in March of 1959. So we are 9 months away from our Supergirl.
I also wish I could find the letter column covering this issue to see what the letters were like to see if there was a feel about the fans' take from there.
I do wonder if the 'feel' of this story defined how Kara Zor-El would be treated in her own stories. If this was wildly popular, the writers might have decided to continue the relationship we see here between Super-Girl and Supergirl.
Lastly, I am presenting this from my copy of Supergirl Archives Vol. 1. If you see this in reprint form in other comics, they usually color Super-Girl's costume as green and orange and make her a redhead. It differentiates her from Kara and makes it less confusing. But in the original coloring (as presented here) she is in the red and blue.
On to the story.