by David Mitchell
These problems are from "Diabolical" a life and death training book. The book is (110pp) with 100 training problems to help strong players improve their reading skills.
There are NO answers in the book, this is in line with other Dan level training material.
Each problem contains at least 4 tsumego positions. In the book Black plays first but on TsumeGo Hero it could be White. The player with sente has the first move only, after that moves alternate as in a normal game.
To solve the problems the player with sente must prevail in all positions on the board. They must defend their own groups and kill any of their opponent's group under attack - with a single move. All positions are resolved without ko, if you find a ko you are wrong.
You can purchase a copy of the book here.