３００回用に「３００」に関わるネタをずっと探してたんだけど、どんなに考えてもガチムチスパルタ兵の雄っぱいしか浮かばなくて、結局連載開始に救われた形に
Source: https://twitter.com/Strangestone/status/1328118024033820673

月曜日のたわわtwitter連載（？）は２０１５年２月２３日（月）から、祝日とか関係なく毎週月曜日に投稿を続けてきましたので、ナンバリングを見ていただければ時の流れの速さを正確に痛感していただけます。開始時にはまだ幼稚園の年長組だったお子さんでもそろそろ小学校を卒業しようかという文字数
Source: https://twitter.com/Strangestone/status/1328148992400580609

今週は３００回＆連載開始記念です
Source: https://twitter.com/Strangestone/status/1328170933136355330

I'd been hunting this whole time for a "300"-related gag for the 300th installment, but no matter how I tried, all that came to mind was muscle-bound Spartan man-boobs, so in the end, I was saved by the serialization kicking off.
Source: https://twitter.com/Strangestone/status/1328118024033820673

The Twitter serialization(?) of "Tawawa on Monday" started on February 23, 2015 (Mo), since which I've continued to post it every Monday, regardless of national holidays, so I can get you to have a full sense of how fast time flies by having you look at the numbering. The word count's high enough that kids who were older kindergarten students when this started would now be ready to graduate from elementary school.
Source: https://twitter.com/Strangestone/status/1328148992400580609

This week's themes are "Episode 300" and "Commemorating the Serialization Starting".
Source: https://twitter.com/Strangestone/status/1328170933136355330