Braulio forces his opponent to the reverse de la riva guard and when they begin to move with the intention of spinning underneath him, he grabs their wrist and side steps before backstepping and transitioning to the top of reverse half guard. From there, he uses his control of their wrist to finish with a 1 arm kimura. Additionally, when they hold onto the reverse half guard after his backstep, he has the option of transitioning to a 3/4 mount and finishing the kimura from there instead.
Links to other Parts:
Part 2