Ken Takakura did not receive an Oscar nomination for portraying Ken Tanaka in The Yakuza.
Takakura's performance works particularly well as a companion work to Mitchum's and a contrast to it. On the one side of it Takakura is very effective, as Mitchum is, in the action scenes. He brings the right type of "cool" so to speak in these scenes though Tanaka takes on foes with the sword while Harry uses a gun. As with Mitchum the action scenes are never something taken lightly within Takakura's performance, although he technically goes even further with this partially due to the overtly physical nature of the action he participates in. Takakura brings a real weight to every moment by portraying every ounce of the battles in his own performance. This is in part due to realizing the physical exasperation of the fight, particularly in the final duel, but he also captures the emotional intensity involved. The fight becomes very personal for Tanaka, partially due to honor partially due to loss, and this is never lost in Takakura's performance. In every moment of the fight what motivates the man is keenly felt and makes every action scene all the more compelling because of this.
Again the contrast against Mitchum though is what is truly remarkably in this as Harry is the man we know pretty quickly, but Tanaka is the mystery of the film, the mystery who slowly unravels in order for us to understand. Takakura's performance is always in an exact tandem with this unraveling and through this makes the most compelling aspect of the film. After the initial rescue, which only leads to greater problems for Ken, which Harry tries to help him with. There's a great scene for Takakura where Harry tries to counsel him on what to do with his severe problem involving honor and the Yakuza where Ken's life is on the line. Takakura is amazing in the scene because every line of delivery has an abruptness, even a coldness of a man who doesn't care much about what Harry is saying, and just will do what he needs to do for himself. In every words about Harry, particularly when Harry speaks about his "sister's" concern for him, there is such a palatable anguish within Takakura's eyes. Takakura is deeply affecting as a reveals the real man suffering beneath essentially the requirements of honor, alluding to what the man is really going through even before we learn what that is.
Takakura is terrific in keeping in this dual nature of the man as he does portray an absolute conviction within the honor, yet there is always the sense of the sacrifice this entails. Takakura keeps in mind this idea throughout his performance though in every moment large or small, in even a slight reaction such as watching Harry being embraced by his "sister", there is those subtle hints to the far more vulnerable man who is burdened by his giri, his obligation, due to when Harry's past actions saved his "sister's" life. Eventually we learn the truth of the man which is that Harry never had saved his sister but actually his wife, and his honor left him to support Harry even as the two had an romantic affair. This revelation is bluntly revealed in a heartbreaking moment as grieves over the death, due to a gunfight, of his thought to be niece but was in fact his daughter. Takakura reveals the severity of the loss in revealing the out pour of almost the full anguish of the man's life. That is not only an incredibly powerful moment in the scene itself, but looking at the revelation naturally grants an understanding to the whole of Takakura's performance.
With this mystery revealed Takakura's performance is interesting in that it is the same yet with the perspective of knowing the truth you see every moment of the man in a different and very poignant light. In that way we are much like Harry in the film who by the end comes to fully understand the sacrifices of Tanaka himself. This leads to the two men coming together to realize a friendship between the two. It's a great scene for both actors though especially so for Takakura. Takakura in the moment loses that tension between the two sides of the man as Harry offers his apology. Takakura opens up most honestly emotionally in the moment, no longer is directed around any pain, no longer with the distance to the man who both righted and inadvertently wrong him. There is such an earned tenderness and respect in his delivery of "No man has a greater friend" which is both heartwarming and devastating as we see that two men finally fully knowing one another. This is a great performance by Ken Takakura as he provides the hidden heart of the film through his slow dissection of this initial enigma of a man that grants a real substance to the film that elevates the potentially pulpy story.