Hirokazu Yasuhara
From Sega Retro
His works:
Sonic the Hedgehog - Game Planner ("Carol Yas") Sonic the Hedgehog 2 - Game Planner, Object Placement Sonic the Hedgehog 3 - Director, Lead Game designer Sonic & Knuckles - Director, Lead Game designer Sonic 3D Blast (Sonic 3D: Flickies' Island) - Playfield Design, Saturn Enhancements Sonic R - Map Design Director