It’s no secret that Bill Belichick’s coaching tree is one of the most impressive that the game of football has ever seen. When NFL, and even college football, teams find themselves with openings, there are a lot of decision makers that want to pluck someone from the Patriots dynasty during Belichick’s time in New England.

While coaches that have worked under Belichick and gone on to their own NFL opportunities haven’t been able to translate that same type success to their new stop as of yet, Belichick has had an impressive 9 assistants (pending Brian Flores’ appointment with the Dolphins after Super Bowl LIII) under him go on to head coaching jobs. A total of 7 coaches that worked under Belichick at one time have gone on to college head coaching jobs.

There’s certainly a well calculated method to how Belichick prepares for everything that comes across his desk as he prepares for games, and Yahoo! Sports outlined a specific task he gives to his young assistants that they both have a deep appreciation for, and loathe beyond question.

The task is called “padding games.”

As Yahoo! points out:

When padding games, assistants are required to watch tape of a given game and — on every single play — draw the offense and defense on a sheet of paper, and map out the movement and assignment of each player on the field. They’re also asked to note everything from receiver and offensive-line splits to tendencies and protections, along with deeper observations about what players on each side are trying to accomplish on the play.

Assistants are given the responsibility of padding four our five games of upcoming opponents at a time, and a single game can take anywhere from seven hours to a couple of days.

Offensive coordinator Josh McDaniels, who left the Patriots for a two-year run as the head coach of the Broncos from 2009-10 before returning to the staff, cites padding games as the the most important things he’s ever done as an assistant.

“I think the most important thing young people have got to understand is, it’s not a punishment. It’s a tremendous opportunity to learn how important everything is at this level,” McDaniels shared.

Head here to read the full piece, including more input from current and former Patriots coaches on the value that the exercise has provided them in their coaching development.