Kanae Kijima was convicted of three murders in 2012 without a confession and without a witness to any of the three deaths, which is unusual in a Japanese prosecution. She has maintained her innocence throughout, her account being that the money was given to her freely and that the men died by accident or by their own hand.
On August 6, 2009 Yoshiyuki Oide, forty-one, a company employee from Tokyo's Chiyoda Ward, was found dead in a rented car in a parking lot in Fujimi City, Saitama Prefecture, with a charcoal burner. The briquette burner was then the standard method of carbon monoxide suicide in Japan, and it looked like one. It did not hold together. There was no key to the rental car in it. The briquettes seemed to have been lit with a match left near the car, but there was no matchbox. There was no charcoal residue on his hands, and no gloves.
The Saitama police went to the woman he had been seeing. She was thirty-four and unemployed, and several of the men she had been with before him had died in doubtful circumstances. She had been posing as a prospective bride on marriage-hunting sites, and on September 25 she was arrested for fraud.
She was born on November 27, 1974 in Nakashibetsu, Hokkaido, and grew up in Betsukai, where she went through elementary, junior high and high school. The universities she attended afterward are reported two ways: the economics faculty of Toyo University in one account and, briefly, the University of Tokyo in another. She did not graduate from either. Her first recorded offense came in her teens, when she and her boyfriend, a man of forty, stole eight million yen from an acquaintance. She was given probation because she was a minor.
She told people she lived in a luxury condominium in Nishi-Ikebukuro at two hundred thousand yen a month and drove a Mercedes-Benz, which was rented. Using the name Sakura Yoshikawa she said her father taught at the University of Tokyo and that she was a piano teacher and a food coordinator. The Japanese press called her the Konkatsu Killer, after konkatsu, marriage hunting, and also the Black Widow.
Takao Terada, fifty-three, a salaried worker in Ome, was found dead in his home on January 30, 2009, of carbon monoxide poisoning. Just before he died seventeen million yen had moved from his bank account to hers. His computer and keys were missing. The prosecution said he could hardly have bought twenty kilograms of charcoal briquettes: he had no car or bicycle, had never rented a car, and there was no record of an online order. His death was treated as suicide and there was no autopsy, which made the murder charge laid on February 22, 2010 an unusual one.
Kenzo Ando, eighty, of Noda, died on May 15, 2009 in a fire that burned his house to the ground, with briquette burners placed near his body. His father had been a well-known painter, and she took paintings from the house to sell. Straight after his death she withdrew 1.9 million yen from his account. He had never taken sleeping pills, yet more than ten times the usual dose was in his body, and the autopsy found almost no soot in his throat.
Oide had given her about 4.7 million yen, after she let him believe she would marry him; other reports put the sum at five million.
She was suspected in other deaths too. Sadao Fukayama, seventy, was found naked in the bathroom of his home in Matsudo in August 2007, of causes never determined, after giving her seventy-four million yen. None of those deaths was charged. By January 2010 she had been rearrested on seven counts of fraud, against men in Shizuoka, Nagano, Saitama and Tokyo, some of whom she was still courting when she was caught; a forty-year-old man from Chiba who had given her 4.5 million yen was living with her when she was arrested.
The trial at the Saitama District Court joined everything: three murders, six counts of fraud or attempted fraud and one of theft. It began on January 10, 2012 and ran a hundred days under the lay judge system. The prosecution's case was that the briquettes and other items found at each scene had been bought by her beforehand, that she had drugged each man and lit the burners, and that each had last been seen with her. There was no direct evidence of any of it, and the prosecutor told the court so in a metaphor: nobody sees the snow fall in the night, but in the morning everyone can see that it has.
On April 13, 2012 the presiding judge, Kazuyuki Okuma, found her guilty and sentenced her to death. She was the first woman condemned by a lay judge court, and she appealed the same day. The Tokyo High Court dismissed the appeal on March 12, 2014. The Supreme Court heard argument on February 10, 2017, where the defense said again that the men might have killed themselves, and on April 14, 2017 it dismissed her final appeal unanimously. The presiding justice, Yoshinobu Onuki, said the killings were deliberate and extremely malicious, her explanations irrational, and that she showed no remorse. On May 9 the court rejected her claim of bias. She was the fifteenth woman condemned in postwar Japan.
What has happened since is the part of the case that has no real parallel. Prisoners under sentence of death in Japan ordinarily disappear from public view. Kijima has not. She has kept up a blog through her lawyers, before, during and after the trial, and since 2014 supporters have run one that carries her writing. She publishes on the conditions in the detention house, the food, the biscuits available, dietary advice, and the workings of the lay judge system. Her memoirs and fiction have run in the magazine Josei Jishin, and Kadokawa published a novel of hers in 2015. She married in custody, by some accounts twice, and in 2016 took the surname Doi. She has been held on death row at the Tokyo Detention House since 2019.
She has also used that platform to attack the coverage of her own case. Japanese reporting dwelt heavily on her appearance and her weight, treating both as evidence that her account of men falling for her was implausible, and she has sharply criticized the focus on her looks and her gender over the legal evidence.
That argument reached a general audience through fiction. Asako Yuzuki's novel Butter, a bestseller in Japan, takes its starting point from the case and is about media misogyny, body shaming and the treatment of a woman accused. It was published in English in 2024.
She remains under sentence of death: three murder convictions affirmed unanimously by the Supreme Court, in a case with no confession, no witness and no direct evidence of the act. Chisako Kakehi, convicted on comparable evidence of poisoning men she had married or dated, died in prison under sentence of death in December 2024.