In which cherub book does James earn his black shirt?

The Cherub series does not feature a character named James who earns a black shirt. The series focuses on a group of child spies called "Cherubs" who are trained by the British intelligence agency known as "The Agency."

Within the Cherub series, earning a black shirt is a significant achievement for a Cherub, symbolizing their advancement and their ability to take on more dangerous missions.

The characters who achieve this distinction in the series are:

* James Adams - the protagonist of the series, earns his black shirt in the book "The Recruit".

* Lauren Adams - James's younger sister, also earns a black shirt, though the specific book where this happens isn't as clearly defined. It's likely to be in the book "The Fall" where she is fully integrated into the Cherub program.

If you're thinking of a different character or a different series, please provide more details!