They Were Eleven is a manga that tells a more interesting story in one volume than some other manga tell in ten times that amount. It is a shoujo, but it doesn't fall for any of the usual tropes that make the genre boring. It is a pleasant surprise that is still an enjoyable read even almost fifty years after its release. The core concept of the story is somewhat "classical" - group of people gets stuck in closed area and as the days go by some of them grow less and less irrational and the conflicts inside the group grows. This time with the additionof everyone knowing right from the start that there is an odd one out, someone who doesn't belong, thanks to which the story can progress faster and can be contained within one volume.

While the story alone would be enough for an enjoyable read, what I especially liked about this manga is the worldbuilding it managed to create in such a short time - namely the various cultures and biology of different planets, and how this is incorporated into the side plot and character growth of certain part of the cast.

Overall this is definitely a worthwhile read and you should give it a try even if you're not a fan of older manga or shoujo genre.