“I Trust My Husband”: Trial of Woman Who Stabbed Her Husband’s Mistress in the Head—Husband and Eldest Son Defend Her, but… All Eyes Are on the Verdict

The defendant entered the courtroom with a model-like tall figure and beautiful long hair

The first hearing for defendant Aiko Kobayashi (58), who is charged with assault for slashing a female acquaintance with a knife at a hotel in Shinjuku Ward, Tokyo, was held on June 18 at the Tokyo District Court.

“The incident took place at a restaurant in the ‘Riga Royal Tokyo’ hotel in Shinjuku Ward. Around 9:00 a.m. on April 10, defendant Kobayashi attended a dinner party with her husband, where she ran into Ms. A—the victim in this case—who had been having an affair with her husband for many years.

Kobayashi got into an argument with her husband right there and stabbed Ms. A in the back of the head with a knife, among other acts, and was arrested on the spot on suspicion of attempted murder.Ms. A sustained injuries expected to take two weeks to heal, while her husband suffered minor injuries. At the time of her arrest, Ms. Kobayashi admitted to the crime, stating, “There is no mistake,” but regarding her motive, she stated, “I don’t remember.” (Reporter, Social Affairs Department, national newspaper)

Defendant Kobayashi appeared in court wearing a gray sweatsuit. Since she was wearing a mask, it was impossible to gauge her expression. Perhaps because she had been in custody, gray hair appropriate for her age was visible at the roots, but her model-like height and beautiful long hair were striking.

When she took the stand and the judge asked her occupation, she replied , “I am a full-time housewife and unemployed.” Regarding the indictment, she acknowledged, “There are no particular errors.” What emerged during the trial was a drama of love and hate stemming from a middle-aged love triangle.

According to the opening statement read by the prosecution, Defendant Kobayashi worked at an advertising agency after graduating from university. She married her husband and had three children. However, her husband had affairs with multiple women, and for many years, Defendant Kobayashi reportedly struggled with her husband’s infidelity.After her husband’s affair with Ms. A was discovered, Ms. Kobayashi and Ms. A exchanged messages directly via LINE. Their exchanges frequently devolved into arguments, and Ms. Kobayashi even filed a lawsuit against Ms. A for adultery. As a result, Ms. A submitted a letter of apology to Ms. Kobayashi for continuing the affair, and the two reached a temporary settlement.

However, Ms. A continued to harass Ms. Kobayashi—including making silent phone calls—which caused Ms. Kobayashi to develop an adjustment disorder and other conditions. Then, on the day of the incident, a tragic confrontation occurred when Ms. Kobayashi and Ms. A ran into each other.

According to Ms. A’s written statement, she harbors strong feelings of resentment toward Defendant Kobayashi, stating, “I seek the harshest possible punishment.”

The first person to take the stand as a character witness was the attorney who had been advising Defendant Kobayashi.

He explained her mental state at the time, stating, “She was mentally exhausted from being harassed by her affair partner.” Regarding the defendant’s husband, he described him as “a rather unusual husband” and testified that “the defendant is an ordinary person who lacks the strength of character to continue the relationship [with her husband].”

According to the defendant’s eldest son, who took the stand next, he had received an email from the defendant on the day of the incident that read, in essence, “Mr. A is here. Help me.”

The Cruel Words and Actions of a Cheating Husband Toward His Mistress

“About a week before the incident, he was constantly asking for help. I regret putting my mother through such a hard time all by herself,”

he said, hanging his head. As the eldest son, he had repeatedly tried to reason with his father, but he also struggled with the fact that “no one could stop him.” However, regarding his father now, he noted that he has started going straight home, and

“My father has been saying things like, ‘It’s all my fault. I’m so sorry to Mom.’ He’s telling [Ms. A] to withdraw the police report,”

he revealed, describing the change.

Finally, defendant Kobayashi took the stand and

　“Regardless of the reason, I would like to apologize for causing her pain,”

and bowed his head before the cross-examination began. He recalled the day of the incident while answering his attorney’s questions. He and his wife had attended the dinner party as hosts at the organizer’s request. At the party, he spotted Ms. A and endured what he described as a painful ordeal, all the while thinking , “I wanted to go home early.”

When the dinner party finally ended, she settled the bill and asked her husband, “What are we going to do now?” He brushed her off, saying, “It’s obvious—I’m going home with A.” At that moment,

“Twelve years of endurance (Editor’s note: Presumably the duration of her husband’s affair with Mr. A) came crashing down. After that, my mind went completely blank, and my memory of the events became fragmented,”

she said, insisting she has no memory of the moment she attacked Ms. A with a knife. When asked about her husband,

“He came to visit me and cried his eyes out. In our 25 years of marriage, it was the first time he’d ever cried for me. I believe his promise to break up with [Ms. A],”

she said. The prosecution condemned the crime as “dangerous and relentless” and sought a two-year prison sentence. On the other hand, the defense argued that her husband and Ms. A had been in an extramarital affair for many years and that “there are extenuating circumstances,” requesting a suspended sentence.How will this middle-aged love triangle end? The verdict is scheduled to be handed down on July 1—