The Sword of Kaigen

The Sword of Kaigen (2018) is an adult fantasy novel by Chinese American author M. L. Wang. Heavily inspired by Japanese culture and martial arts, the novel has been compared to Lian Hearn’s Across the Nightingale Floor and R. F. Kuang’s The Poppy War. Set in a fictional world featuring people called theonites who possess magical abilities, Sword of Kaigen follows Misaki and her son, Mamoru, members of a warrior class who face a dire threat to their isolated mountain village. The novel features a blend of intricate world-building, deeply complex characters, and intense fight sequences, through which the author conducts an empathic exploration of the impact of war and trauma, the line between truth and propaganda, and the path toward redemption.

This guide refers to the 2019 paperback Amazon self-published edition.

Content Warning: Both the source material and this guide contain depictions of graphic physical violence and war-related deaths, the death of a child, sexual assault, rape, domestic abuse, suicidal ideation, suicide, miscarriage, and references to infanticide.

Plot Summary

Mamoru and his mother, Misaki, live in the mountain village of Takayubi, in the Shirojima Province of the Kaigenese Empire. As members of the warrior family, the Matsudas, they are expected to uphold the family’s honor and remain true to their power as jijakalu (water and ice wielders). Mamoru attends the elite Kumono Academy, where he meets transfer student Kwang Chul-hee. Chul-hee shocks Mamoru with the revelation that the history he has been taught is largely built on propaganda that is designed to keep the Shirojima warrior houses—known collectively as the Sword of Kaigen—under control so that they will remain willing to sacrifice their lives for the Empire.

Meanwhile, Misaki remains at home, dissatisfied with her role as a housewife and regretting her choice to leave her former life. When she was a teenager at an international school, she was once an accomplished warrior and vigilante with her friends, including her lover, Robin. However, she left Robin and that life behind when her father ordered her to marry Matsuda Takeru, a cold, distant authoritarian. Over 15 years of marriage, Misaki has become timid and silent. Her only comforts are her sister-in-law, Setsuko, and her friend, Hyori.

Over several months, Mamoru learns more about the lies that the government spreads to keep the people complacent, and he grows uncertain about his place in society. Then, a series of storms hit cities and villages along the coast of Shirojima. Mamoru realizes that these storms are a government cover-up to hide attacks from the neighboring Ranga Union. When he shares his suspicions with his father, Takeru calls him a traitor and challenges him to a duel, which Mamoru loses badly. To help, Misaki reveals her past as a fighter and trains her son in secret, defying Takeru’s wishes.

Later, Misaki receives a letter from her former Ranganese roommate, warning that the Ranganese are about to attack Takayubi. Misaki gathers her children to run, but before she can escape, the attack begins. Takeru and his older brother Takashi leave to defend the village, taking Mamoru with them despite Misaki’s objections. Misaki stays behind to defend the house.

The Ranganese attack is brutal and overwhelming. Many men die, including Takashi. Before his death, Takashi orders Takeru to protect the family and directs Mamoru to protect the nearby village of craftsmen. Mamoru dies fulfilling this duty, and although no one else ever knows of it, he becomes the youngest person in history to master the Matsuda family’s magical technique, the Whispering Blade.

At the house, Misaki retrieves her long-forgotten sword and kills many Ranganese attackers. Then, reinforcements from the military arrive and prepare to bomb the village. Takeru arrives to take the family to a nearby shelter. On the way, Misaki learns that her friend, Hyori, is missing, and she goes looking for her. She finds Hyori being raped by a Ranganese soldier. Misaki kills the soldier, and they flee to the shelter together. There, Misaki learns that Mamoru is dead.

In the aftermath, the villagers look to Takeru for leadership. However, he proves unable to handle the responsibility and leaves Misaki and her sister-in-law, Setsuko, to take charge. Misaki’s brother, Kazu, arrives to offer aid. Officials from the Kaigenese military, led by Colonel Song, also arrive. Song and the military take the dead and burn them in a mass grave to cover up the Ranganese attack. Misaki and the villagers ask Takeru to stop Song and protect their rights to give their loved ones a proper burial, but Takeru cowardly bows to Song’s authority and flees.

Filled with rage, Misaki challenges Takeru to a duel, blaming him for their son’s death and for failing the village. To her surprise, Takeru accepts his guilt and offers up his life. He explains that ever since his abusive childhood, he has had a mystical ability to become one with the mountain and thereby escape his emotions. He admits that he uses this ability to retreat from reality rather than face difficult choices. Hearing this, Misaki delivers him a new challenge, declaring that Takeru must accept responsibility to properly lead the village and make up for his failures. To prove that he is capable, he must fight her now as an equal.

They duel, and Takeru is shocked by Misaki’s strength and skill. She nearly overpowers him until he crafts a Whispering Blade strong enough to block her. At last, they reach an understanding and return to the village. On the way, they are attacked by an assassin whom Misaki suspects is connected to her past as a vigilante. Misaki tries to question the assassin, who dies by suicide. 

Later, the military returns to offer aid in exchange for Takayubi’s obedience. Takeru refuses their aid and vows to rebuild Takayubi without the government’s help. He presents his plans to the village, proving his intelligence and resolve, and the villagers rebuild together. During this time, Hyori discovers that she is pregnant with the Ranganese soldier’s child. She gives birth but then dies by suicide, unable to face the shame she feels. The villagers want to kill the infant as well, but Misaki saves her and delivers her to a nearby orphanage. 

In the spring, Misaki is shocked when Robin visits; he has been invited by Takeru, who says that he wants to give Misaki closure. Robin and Misaki reconnect over several days, after which Robin returns home. Misaki realizes that she still loves him, but she also loves Takeru and is finally satisfied with the life she has chosen.