In World War Z, the Tatenokai, or Shield Society is a Japanese defense force dedicated to ridding the Home Islands of the Living Dead. The semi-religious group focuses on melee combat, and rejects the use of firearms. By the time of the novel, the Tatenokai had proven so successful that it was officially adopted into the JSDF.
The Tatenokai was founded and currently led by Tomonaga Ijiro, a blind former garderner and survivor of the atomic bomb that destroyed his hometown of Hiroshima in World War II. Tomonaga runs the group with his co-founder and current second-in-command Kondo Tatsumi, a former high school student, computer hacker, and shut-in.
In WWII, Tomonaga became a "Hibakusha" literally "explosion-affected person". Hibakusha and their children were (and still are) victims of severe discrimination due to lack of knowledge about the consequences of radiation sickness, which people believed to be hereditary or even contagious, as well as living symbols of their nation's defeat. Being among these people was shameful enough, but being blind made him a burden to others too. He tried to kill himself many times, but his inability to go through with it made him perceive himself as a coward as well. Running away from his home in shame, Tomonaga eventually became friends with an Ainu gardener, who personally gave him a job at the Akakaze hotel in Hokaido. Tomonaga continued with this job for years after his friend's death until the day he started hearing about mysterious murders. The rumors persisted as the crisis grew larger, and after hearing his manager's poor attempts to ease the situation, Tomonaga decided to leave for the wilderness, not to protect himself, but to keep from being a shameful burden to others.
Tomonaga managed to survive for several month in quiet isolation in the Hiddaka Mountains. However during an incident when a bear (which he thought was meant to kill him) alerted him to an approaching zombie, Tomonaga decided to live until he discovered why the Kami (nature gods said to inhabit everything) had spared him. For several months he managed to survive against the increasing number of zombies he began to encounter armed only with his gardening shovel, using both his remaining heightened senses to detect the ghouls with plenty of time, and his knowledge of the advantageous terrain to ensure his victory against the ghouls. During this time, he once again became a Shinto-Buddhist, always burying his kills and praying to the Kami for their assistance. When he ran into Kondo Tatsumi, Tatsumi updated Tomonaga on Japan's evacuation to Kamchatka.
Tatsumi himself was an otaku, who had spent the early months of the Great Panic online, feverishly gathering information as his way of escaping reality. Reality rudely intruded one morning, as Tatsumi awoke to find that the power was out and he couldn't connect to the internet. His subsequent breakdown was heard by several ghouls who tried to get into his apartment. Tatsumi survived by creating a rope out of sheets and moving from one floor to another from the outside balconies, gathering whatever supplies he could from each apartment. While his relentless information gathering had granted him all of the knowledge he would need to deal with the zombies on an intellectual level (such as knowing he had no need to run from the shambling ghouls), the ordeal of climbing made him realize just how physically weak and out of shape he was. His encounters with the corpses of his neighbors in their own apartments - including a girl he had a crush on who had committed suicide - forced him to realize just how much he had wasted his life. He eventually made his way into the apartment of an elderly (and now reanimated) neighbor, covered with pictures and memorabilia of a full and happy life. Tatsumi vowed that from that day on he "would live", rather than rot behind a screen. Realizing that the old man was a soldier of the Japanese Imperial Army during WWII, he found his now-undead neighbors' real (and quite sharp) officer's katana in an old foot locker, with which he managed to escape the city alive. He made his way into the forest, where he ran into Tomonaga.
Tomonaga was suddenly struck with a divine inspiration, where the two, along with whatever survivors they could find, would "cleanse the garden of Japan” of the undead “pests”, a daunting task indeed, although Tomonaga felt confidant that the “gods” were on their side. The subsequent success of the Tatenokai proved Tomonaga's faith. The Tatenokai is the modern-day successor to the mythical Society of Life, which supposedly had kept Japan zombie-free during the Tokugawa Shogunate.
The group is based on the historical Tatenokai, which was a private militia in Japan led by the right-wing author Yukio Mishima. Mishima founded the Tatenokai in 1967, recruiting its membership primarily from the staff of Ronso Journal, an obscure right-wing college newspaper. In an unusual move, the Tatenokai was granted the right to train with the nation's armed forces, the Jieitai. In 1970, a group of Tatenokai briefly seized control of the Jieitai's headquarters and attempted to rally the soldiers to stage a coup d'etat and restore imperial rule. When this failed, Mishima and Masakatsu Morita, the Totenokai's main student leader, commited seppuku or ritual suicide.