Posting the rest of the already-written early chapters of Yuusei (El Hermano, 10D)'s book in google doc format. I already posted chapter 1 before, but this includes chapter 1 too because why not.
https://docs.google.com/document/d/1DsQ-5DyOVZIIImbG1kjAS1Nh74sSWxF-QvrgBqowkbY/edit?pli=1&tab=t.0

Chapter 2 is about handling floating tiles in a standard hand when you already have 5 blocks and when to swap them for safe tiles. It's also a simple topic considering it's still chapter 2, but I personally think the content of the chapter might actually surprise some decent players.
Chapter 3 is just about peak 1-shanten theory which you've probably already read about in other books, so this is the most skippable one, but in the context of chapter 2's advice it had to be included.
I've made contact with the person who translated the rest of the chapters now. At some point (not sure when) I might update the book to v2, including the first 3 chapters in some form (maybe not the same as they are here) and making small edits to the rest of the book. It probably won't look like these first 3 chapters because that would be a big rewrite of the entire book, but I haven't decided how to do it yet.