It wasn't cancelled at when that happeneds (vol5-6). This arc happened because Nagai was getting so much criticism from parents, teachers and what not that he decided to change the main plot from perverted jokes to war where everyone is killed. This ends what is called part 1. Part 3 ended and was cancelled because at the time Nagai wanted to focus on Mazinger Z which released in the same magazine.It sounds like the author decided to kill most of the cast because of the incoming cancellation, is this the reason for the infamous arc?
I'm using the digital version which is 11 volumes the original 13 volumes included punch of not directly related one shots in some volume to pad them out. Part 2 starts in volume 6. Part 3 in volume 8. And "4" is the Bearded Godzilla back story at end of volume 11.So glad you're translating this Android and the scans are perfect quality. Also is there an outline of which parts start when? If Part 2 starts at Vol 5 when would Part 3 start? I also assume this is using the original 13 volume count