Roberto Satoshi de Souza is the longest-reigning world champion on the RIZIN FF roster and he’s just had his next title-defense booked for RIZIN 51 on September 28th, 2025. Satoshi was an elite BJJ competitor once upon a time but he is now best-known for his fantastic MMA career. He joined RIZIN FF very early on and worked his way to the top of the lightweight rankings there, eventually getting a chance to fight for the inaugural title back in 2021. Satoshi was 11-1 at the time and he won the belt in decisive fashion, registering one of many first-round submission finishes throughout his career.
Satoshi has had 9 fights in the years since then but not all of them have been title-fights, and some have even been as part of the Bellator and RIZIN FF cross-promotional events. He’s been successful in 4 title-fights during that time and has won every one by submission, including his first-round finish at the 10th anniversary event on New Year’s Eve last year. He’s already had one fight this year too, another submission finish in under a minute and his fourth consecutive win. Satoshi’s record now stands at 19-3 with 18 finishes and he’s established himself as one of the beat lightweight fighters in the world right now.
His next opponent is another tough one though, as Yoshinori Horie is a veteran of almost 20 fights himself. He had a very successful career fighting for Pancrase in the beginning and had a single unsuccessful fight in the UFC, but it’s in RIZIN FF that Horie has made a name for himself. He’s gone 5-2 since joining them and is 14-5 overall, with most of his wins coming through the use of his striking. Satoshi has developed excellent striking over the years and should be more than matching or beating Horie there, but it’s his grappling that will give him the biggest advantage and likely secure him the win.
RIZIN FF announced the news that Roberto Satoshi de Souza would be facing Yoshinori Horie in a lightweight title-fight at RIZIN 51 in a recent post to their official Instagram account:
