fat

signed

Shisui was probably stronger at the point of the series where he was introduced, he was slightly older and was said to have the same prowess and level of genius. He also had his body flicker technique which gave him faster combat speed. However, I’d say with Itachi given more development, his Susano’o (Shisui’s Susano’o isn’t canon anyways) with the Yata Mirror Shield and the Totsuka Blade made him “virtually indestructible” Shisui isn’t really displayed with much analytical and combat ability, it’s just talked about. All of it is really just lack of exposure. With genjutsu, the koto amatsukami is said to be the most powerful genjutsu, but it has a nasty cooldown. Honestly, the Uchiha coup de tat was one of the few instances a genjutsu of that caliber would be necessary, as a regular combat maneuver it would be about as effective as the Reaper Death Seal the Izanagi and Izanami though not as drastic in its drawbacks.