Otoya Yamaguchi

1960 Anpo protests

Akao was virulently anti-communist and strongly pro-United States. Thus when left-wing protesters, led by Asanuma and the Japan Socialist Party, staged the massive Anpo protests against the 1960 revision of the U.S.-Japan Security Treaty (known as "Anpo" in Japanese), Akao became convinced that Japan was on the verge of a communist revolution and mobilized his followers to stage counter-protests. Yamaguchi participated in these counter-protest activities, and was arrested and released 10 times over the course of 1959 and 1960, within his first six months since joining Akao's party.

Yamaguchi's involvement with the Greater Japan Patriotic Party involved aggressive anti-communist actions, including disrupting left-wing events with propaganda, which led to repeated arrests (at least 10–17 documented incidents in 1959–1960) for offenses such as assault (throwing glue at opponents, striking individuals), obstruction of public duties, property damage, violence, and power abuse.

Examples include driving propaganda vehicles into venues (causing injuries), physical clashes with leftists and police during Anpo protests, and repeated violations despite parental and party leader warnings to curb aggression.

Due to this chronic pattern of violence, he was placed under four years of protective observation, indicating a disregard for legal consequences.

Over the course of his participation in the Anpo protests, Yamaguchi became further disillusioned with Akao's leadership, which he felt was not radical enough. In his testimony to the police after the assassination of Asanuma, Yamaguchi stated that Akao was always talking about taking out left-wing leaders, but was only interested in protests and media coverage, and that Akao would stop him if he ever tried to act on his words. Later in the interview, he stated that he had resigned from Akao's party in order to "lay [his] hands on a weapon" and be free to take more "decisive action".

Akao, who had known Asanuma since their time on Miyake-jima, described him as “a good person, which makes it regrettable to deal with him” (善人だから始末に悪い), a comment some sources suggest influenced Yamaguchi’s motives alongside Asanuma’s statement labeling American imperialism as the common enemy of Japan and China, as recorded in Yamaguchi’s Memorial of Severing the Traitor. Despite this recognition of Asanuma’s personal character, Akao later celebrated Yamaguchi’s act.

Alongside Akao's influence, Yamaguchi was also inspired by the doctrine of the religious movement Seichō no Ie, particularly through founder Masaharu Taniguchi's writings such as Tennō Zettai-ron to Sono Eikyō (Absolute Theory of the Emperor and Its Influence), which Yamaguchi credited in his interrogation records with helping him overcome personal hesitation and embrace selfless loyalty to commit the act, Asanuma himself supported the founder of this movement, Masaharu Taniguchi. Taniguchi affirmed that Seichō no Ie was neither opposed to the Socialist Party nor aligned with the Liberal Democratic Party.

On 17 June 1960, when a right-wing youth attacked Jōtarō Kawakami, a Christian socialist and an adviser to the Japan Socialist Party, he commented:

On 1 July, together with his comrades, he took part in the establishment of the Tokyo Branch of the All-Asia Anti-Communist League.

On 4 October, while searching for an accordion at his home, he accidentally came across a wakizashi (a traditional Japanese short sword). It had no handguard (tsuba) and was kept in a plain white wooden scabbard. Upon finding it, he said: "I decided that I would use this wakizashi to kill."

After paying his respects at Meiji Jingū, he immediately telephoned Takeshi Kobayashi, chairman of the Japan Teachers' Union (Nikkyōso), and Sanzō Nosaka, chairman of the Japanese Communist Party. He planned to request meetings by telling them, "I'm a university student committee member, and there's something I'd like you to teach me." However, Kobayashi had moved to a new residence, and Nosaka was away on a trip, so he was unable to put his plan into action against either of them, and the attempt failed.

Assassination of Inejirō Asanuma

On 12 October 1960, Yamaguchi was in the large crowd of 2,500 spectators at a televised election debate held in Hibiya Public Hall in Hibiya Park in central Tokyo, featuring Suehiro Nishio of the Democratic Socialist Party, Inejirō Asanuma of the Japan Socialist Party, and Hayato Ikeda of the Liberal Democratic Party. Asanuma was the second to speak, and took the stage at 3:00 p.m.

At 3:05 p.m., Yamaguchi rushed onto the stage and made a deep thrust into Asanuma's left flank with the 33-centimeter replica "wakizashi" he had stolen from his father. He was then swarmed and detained by bystanders. Bin Akao, who was present at the debate, reportedly remarked to someone nearby upon noticing the limited bleeding, "Little boy (Yamaguchi), did you miss your chance?" (坊や、やりそこなったかな). Asanuma was then rushed to a nearby hospital, but died within minutes from massive internal bleeding.

At the time of his arrest at the scene of the murder, Yamaguchi had a notebook in his pocket describing Asanuma's actions as unforgivable, as well as detailing his motivations for the attack.

In this note, he made mention of political controversy surrounding Asanuma's support for the then recently proclaimed People's Republic of China, the June 15th Incident during the Anpo Protests, as well as concerns over Japan potentially becoming communist.

In the days following the assassination, an imperial envoy visited Asanuma's home in Shirakawa Town, Kōtō Ward, to deliver a sacrificial offering (saishiryō) from Emperor Hirohito, Hirohito publicly appealed for public order and obedience to the law. In a speech opening a special session of the National Diet on 18 October 1960, the emperor urged the Japanese people to "esteem the principle of obeying the laws" and to "shun violence", remarks widely understood as alluding to the killing of Asanuma and the unrest that followed. Contemporary observers described the address as the emperor's closest approach to intervening in a matter of grave national political concern since his renunciation of divinity in 1946.

The loss of Asanuma's adroit leadership and the new leadership that followed caused the party to head in a more centrist direction, and deprived the JSP of its ability to present a cohesive message, leading to severe infighting within the party. As a result, the number of seats the socialists held in the Diet continued to decline until the party's extinction in 1996.

Yamaguchi's perception of Asanuma

In his note left at the scene, Yamaguchi accused Asanuma of trying to "turn Japan red." In his subsequent police confession, he elaborated that Asanuma was a political opportunist who had repeatedly switched sides: a pre-war leftist who turned right-wing when suppressed, then "shamelessly switched to the left" after the war. Yamaguchi claimed Asanuma had belonged to the right wing of the Socialist Party until his 1959 visit to Communist China (after which he became increasingly left-leaning), which "exposed his "true communist nature" with the statement that "American imperialism is the common enemy of the peoples of China and Japan," and that he acted as the de facto leader of left-wing struggles including the Anpo protests.

However, Asanuma was a democratic socialist who had long led the right-leaning faction of the Japan Socialist Party. While the JSP sometimes cooperated tactically with the Japanese Communist Party, Asanuma was ideologically distinct from communism. In a speech criticizing the government, he warned that reactionary policies were dangerous precisely because they created chaos that could lead to communism, stating:

The Yoshida Cabinet has completely failed to respond to the passionate feelings of the people. Instead, it blindly follows America in foreign policy, while in domestic policy it races full speed ahead on a reactionary and reverse course. This has given rise to fascist reactionary politics that drive progressive citizens to despair. At the same time, it has created openings for the Communist Party to run rampant, opened the path to both left-wing and right-wing totalitarianism, and placed our homeland and democracy in grave crisis.

Asanuma was known for his pragmatic style, strong working-class appeal in downtown Tokyo, and deep personal reverence for the Emperor, including daily kamidana rituals and remote worship toward the Imperial Palace, traits that stood in contrast with orthodox Marxist-Leninist communism.

In his police interrogation records, Yamaguchi reiterated that he held no intent to criticize the late Asanuma personally. He expressed that he would pray for his soul and offered an apology to Asanuma's family for the sadness and trouble caused by the assassination.

Broader targets and views on the imperial family

In his November 1960 police confession, Yamaguchi compiled a list of primary targets for assassination to curb what he saw as Japan's slide toward communism, including figures like Iwao Kobayashi (Nikkyoso chairman), Sanzo Nosaka (Japanese Communist Party leader), Inejirō Asanuma (his victim), Ichiro Kono, Tanzan Ishibashi, and Koichiro Matsumoto. He extended criticism to Prince Mikasa, brother of Emperor Hirohito, including him on a broader target list. Yamaguchi accused the prince of opposing Kigen-setsu (Japan's National Foundation Day), making statements that denied the imperial family's role, and allowing himself to be "used by the left wing". He expressed a desire to seek the prince's "reflection by some means", interpreted in context as implying potential confrontation or violence, due to Mikasa's liberal and pacifist views, including criticisms of Japan's actions in the Greater East Asia War. No evidence indicates Yamaguchi acted on plans beyond Asanuma before his arrest and suicide.

Imprisonment and suicide

Following the assassination, Yamaguchi was arrested and imprisoned awaiting trial. Throughout his incarceration, Yamaguchi remained calm and composed and freely gave extensive testimony to police. He spoke of goals pertaining to causing the restriction of behavior for future left-wing leaders, as well as a desire to negatively influence public perception of left-wing leaders and their ideology.

Yamaguchi spoke of Akao respectfully, referring to him using the honorific sensei (先生, master), however, also stating that Akao was more interested in "media attention" and "agitation", as opposed to actively putting his words and ideals to practice. Yamaguchi told police that Akao would have prevented him from carrying out the assassination had he known of his intentions, as well as consistently maintaining that he had acted alone and without any direction from others, stating the inaction on Akao's part as a component of his motivation and reasoning for resigning from the party and committing the offense.

In the same confession, Yamaguchi also listed the historical figures he most admired (apart from the Emperor, whom he regarded as absolute and therefore separate):

Less than three weeks after the assassination, on 2 November, Yamaguchi mixed a small amount of toothpaste with water and wrote on his cell wall "Seven lives to serve the country (七生報国, shichishō hōkoku), Long live the Emperor" (天皇陛下万才, tennōheika banzai), the former part a reference to the famous last words of fourteenth-century samurai Kusunoki Masashige. Yamaguchi then knotted strips of his bedsheet into a makeshift rope and used it to hang himself from a light fixture. He was found hanging at 8:31 p.m. and was apparently still alive at the time, but was pronounced dead three hours later after unsuccessful attempts to revive him by artificial respiration.

On 3 November, the day after Yamaguchi's suicide, Kyōko Asanuma, widow of Inejirō Asanuma, held a press conference to address the news. She stated that she had learned of Yamaguchi's death from the morning newspapers and expressed pity for the young man rather than hatred, while directing strong condemnation toward the influences that had radicalized him:

I first learned of Yamaguchi’s suicide this morning through the newspaper. Rather than feeling hatred toward the boy, I feel more pity for him. My anger is burning up from the bottom of my heart once again toward the unseen forces that instilled such dangerous ideas into a 17-year-old boy and drove him to commit assassination.

Her response was widely regarded as an embodiment of the principle of "hating the sin but not the sinner".

Right-wing groups celebrated Yamaguchi as a martyr; they gave a burial coat, kimono, and belt to his parents and performed a memorial service for him. His ashes were interred in Aoyama Cemetery.

Yamaguchi's mother continued to visit Asanuma's grave on the anniversary of the latter's death.

Legacy

A photograph taken by Yasushi Nagao immediately after Yamaguchi withdrew his sword from Asanuma won the 1961 Pulitzer Prize, and the 1960 World Press Photo award. Footage of the incident was also captured.

On 15 December 1960, just weeks after Yamaguchi's suicide, a nationwide coalition of Japanese right-wing groups held a "National Memorial Service for Our Martyred Brother Yamaguchi Otoya" in the same Hibya Public Hall in Tokyo where Yamaguchi had assassinated Asanuma. Since then, right-wing groups have held an annual commemoration of Yamaguchi's death anniversary each year on 2 November. In October 2010, right-wing groups staged a large-scale celebration of the 50th anniversary of Yamaguchi's assassination of Asanuma in Hibiya Park.

Yamaguchi's actions and the massive publicity they received inspired a rash of copycat crimes, as a number of political figures became targets of assassination plots and attempts over the next few years. Of the notable crimes inspired by Yamaguchi's attack, one was the Shimanaka Incident of 1 February 1961. In this incident, Kazutaka Komori, a 17-year-old member of the Greater Japan Patriotic Party, attempted to assassinate the president of Chūō Kōron magazine for publishing a graphic dream sequence depicting the beheading of the emperor and his family. This played a role in establishing what came to be known as the Chrysanthemum taboo.

Japanese author Kenzaburō Ōe based his 1961 novellas Seventeen and Death of a Political Youth on Yamaguchi.

Yamaguchi's assassination and suicide have been critiqued in Japanese sources as heinous terrorism that contributed to perceptions of increasing "brutalization" in post-war juvenile delinquency. His extremism made "patriotism" appear frightening to the public, associating right-wing ideology with violence and evoking fears similar to those of organized crime.

The case inspired ongoing controversy and threats, such as those against author Kenzaburō Ōe for fictional works inspired by the event, perpetuating cycles of intimidation and societal division.