why did yujiro kill his wife

Yujiro Hanma killed his wife, Emi Akezawa, because she challenged him after he defeated their son, Baki. Yujiro was furious and disappointed at Baki for being "weak" and saw Emi's challenge as a forfeiting of her own life. He killed Emi partly as punishment and partly to motivate Baki to become stronger by hating him. Yujiro had chosen Emi because of her bloodlust, believing it would produce a strong child. However, since Baki was not as strong and ruthless as Yujiro expected, Emi became expendable in his eyes. Emi's death was also meant to fuel Baki's hatred and desire to become stronger than his father. Despite this, there are indications that Yujiro respected and even loved Emi in a complex way, as shown by how he killed her—ending with a tight bear hug that signifies both love and regret. In summary, Yujiro killed Emi because she attacked him in defense of their son, symbolically forfeiting her life, and because Yujiro believed it necessary to push Baki towards greater strength through hatred and loss. This act reflects Yujiro's brutal and complex nature and his harsh method of motivating his son.