Senji Nakagawa played a central role in the Yamaichi War, the largest gang war in Japan in the 1980s, as an executive of the anti-mainstream Ichiwakai faction. Known for his moderate and calm personality, he also played a key role as a coordinator within the organization amid the intensifying conflict, but in the end he was killed by a bullet while waiting at a traffic light, a routine event.

Senji Nakagawa played a central role in the Yamaichi War, the largest gang war in Japan in the 1980s, as an executive of the anti-mainstream Ichiwakai faction. Known for his moderate and calm personality, he also played a key role as a coordinator within the organization amid the intensifying conflict, but in the end he was killed by a bullet while waiting at a traffic light, a routine event.

The Yamaichi War started with the death of Kazuo Taoka, the third Yamaguchigumi leader, in 1981. Led by Hiroshi Yamamoto, who opposed the appointment of Masahisa Takenaka as his successor, Yamaichi broke away from the Yamaguchigumi in 1984 to form the "Ichiwakai" (Ichi-wakai Association). This led to a nationwide expansion of the conflict between the Yamaguchigumi (Takenaka faction) and the Ichiwakai (Yamahiro faction). In the conflict, there was a series of shootings, bombings, and murders, and the number of casualties is said to have exceeded 100. Nobuharu Nakagawa was involved in the heart of the conflict as an executive of the Ichiwakai, participating in operations and defense policies, as well as in internal and external negotiations. Although he was rational and avoided unnecessary bloodshed, it is said that he also went to the front lines when necessary.

On January 26, 1985, a meeting of Ichiwakai executives held at the Shin Hankyu Hotel in Osaka was attacked by Yamaguchigumi hitmen. This is known as the "Ichi-Ni-Roku Incident. The attackers entered the venue dressed in suits and opened fire simultaneously with automatic rifles, killing two Ichiwakai executives and seriously wounding several others. Nakagawa was also present at the meeting and was reportedly hit by a bullet, but he escaped with his life at the time. In the confusion, he shouted, "Get down!" and defended his subordinate, showing his calm judgment. However, after this incident, the conflict became even more extreme.

On May 21, 1986, Nobuharu Nakagawa was traveling by car in Osaka Prefecture, waiting at a traffic light at an intersection. At that moment, a hitman from the Yamaguchigumi-affiliated Takenaka clan approached and fired shots at close range. Nakagawa was shot in the chest and neck, and died instantly on the spot. The crime was a premeditated assassination, carried out after having ascertained the pattern of behavior in advance. The murderous act in the midst of an everyday scene at an intersection in the city sent shockwaves throughout the world.

Nakagawa's death was an extremely heavy blow to the Ichi-wakai. With the disappearance of a coordinating and rational executive like Nakagawa, hard-line voices rose to prominence within the organization, and the conflict became even more bitter. His funeral was held under heavy police guard and attended by many concerned parties. Before his death, Nakagawa is reported to have said, "The war is not the pride of the organization, but hurts people who have nothing to do with it," an attitude that is still spoken of today among those involved in the Ichiwakai.

Nobuharu Nakagawa was a key figure in the Ichiwakai, which strove to maintain organizational balance to the very end in the midst of the Yamaichi War, the largest gang war in the history of organized crime. But even his reason could not overcome the logic of violence, and in his final moments, in the quiet of everyday life at a traffic light, he was struck by a bullet. His death symbolized the depth of the struggle between the Yamaguchigumi and the Ichiwakai and how violence can take away reason and life, and it also strongly impressed upon Japanese society the issues surrounding gang wars and their end.