PrimeWire

you might have also noticed “why are all these fellas attacking one by one and mostly from the front? why dont they just rush him like a mob of rugby players? lose maybe one guy, wrestle him down and behead him”
Yes its unrealistic, but this is how japanese people film swordfights, its based on how they fight in traditional japanese theater. Its also evident in the way JRPG computer games work, guys leap in, attack, and go back to thier starting spots with no tactical movement. total bullshit you might say, ofc and thats quite true :) but thats how they do samurai swordfights its traditional.
Another factor here is this film compresses many events in the life of musashi into this single long impossible fight .. the whole thing is a bit of theater and hero worship, but is it really any more impossible than Rambo? any more absurd than wild west gunfighters who stand in the street til the stroke of noon and quickdraw?