This isn't actually KENTA'S debut (or simply Kenta Kobayashi as he was known then before he changed it to avoid the confusion which abounded in All Japan with his teacher, Kenta Kobashi), but it comes from the 31st May which was seven days afterward.
He was 19 years old.

And yes, that is Takashi Sugiura in the background.
Although Sugiura trained at the All Japan dojo, he never debuted there. He was the first person to debut for Noah, which he did in December 2000.

His opponent is Makoto Hashi.
Hashi (trained by Jun Akiyama) was Marufuji's roomate at the All Japan Dojo, and was part of the AJPW walk out. He retired due to neck problems in 2012, and works as a physiotherapist.
He helped put Marufuji back together again in late 2018.

The move that was drilled into them in the All Japan dojo

Marufuji said that one of his earliest memories of KENTA (other than he was quiet), was that he wouldn't give up. He was the only one to stick out the harsh life and grueling exercise of the dojo, and he remembers his grit when Akiyama was training him, physically being no match.

Naturally being only nineteen and a rookie, he hadn't actually developed the move set he would in Noah in later years or the character - for now he was just young Kenta Kobayashi, just seven days old into his career.

The match ended in submission