Tatsuya Nakadai, the one shooting a couple gallons of soda water mixed with chocolate syrup, is the nemesis in both Sanjuro and Yojimbo. Also: Sword of Doom.
I was gonna say, WHY THE HELL DOES DEADGUY (aka: anybody in a black and white Samurai Flick who looks at Mifune the wrong way) HAVE CARBONATED BLOOD!? Thank you for the Psycho redux explanation.
This is so badass you don't even know. Aside from the collision of the themes of honor and violence and commitment in this scene, it's a totally awesome iaido staredown, with the mounting tension and oh man is Sanjuro gonna win or lose? Which is better? BAM! Other guy's gushing blood. Awesome! Fucking awesome!