58 pages • 1-hour read
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Content Warning: This section of the guide includes discussion of domestic abuse, gender discrimination, suicidal ideation and self-harm, attempted death by suicide, graphic violence, and death.
Testuya Ishigami is one of the three point-of-view characters and the primary culprit of the crime in the novel. His genius-level intellect is admired by Yukawa, who calls him “Ishigami the Buddha” (71) due to his single-minded focus on mathematics and logic. However, despite being a promising student in graduate school, Ishigami did not become a university professor, as Yukawa assumed he would. Instead, due to a series of professional and financial setbacks, he was forced to settle for more stable work as a high school mathematics teacher. He is deeply unsatisfied with his life, and prior to the opening of the novel, he once considered suicide.
A middle-aged, heavy-set, and balding man, Ishigami never cared about his appearance in the past, but his feelings for Yasuko have made him self-conscious about his looks. (Yukawa notices this change in his personality.) Ishigami is straightforward and approaches everything in life like a math equation. Because he is unemotional and often expressionless, others find it difficult to understand him. Due to his unemotional nature, no one initially suspects him of having romantic feelings for Yasuko or of being her accomplice.
Ishigami is motivated by his love for Yasuko and by his belief that she saved his life merely by arriving at the right moment on the night that he planned to die by suicide. He views Yasuko’s presence in his life in a similar fashion to “his relationship with mathematics: it was enough merely to be associated with something so sublime,” and he believes that “[t]o seek any kind of acknowledgement would sully its dignity” (291). This selfless, obsessive love drives his every action, forming the core of the novel’s focus on The Morality of Love and Self-Sacrifice. He also competes against Yukawa in the intellectual conflict of the plot. The complexity of Ishigami’s motives and of the friendship he shares with Yukawa complicate the novel’s depiction of legal justice, contributing to the theme of Navigating Imperfect Justice and Moral Ambiguity.
Yasuko Hanaoka is the second of the three point-of-view characters. She is a divorced single mother who has a daughter named Misato. Yasuko works at a lunchbox shop called Benten-tei, but she previously worked as a club hostess at Club Marian. Several characters describe Yasuko as pretty and personable, though she characterizes herself as having “no great allure” and “hardly any redeeming qualities” (283). She has been married twice; her first husband is the father of her daughter, while her second husband, Shinji Togashi, developed an alcohol addiction and became abusive during their marriage. Although she has since divorced him, he often harasses her and extorts her for money, and she has been forced to move several times in order to avoid him.
Yasuko lives in a society that often dismisses the concerns of women. This underlying societal gender discrimination contributes to the times when she gave in to Togashi’s demands, and this cultural imbalance also explains her impulsive decision to kill him; she feels that she has no legal support and therefore no other choice. Simultaneously, Yasuko has a narrow, self-centered view of life, primarily focusing on her problems and her daughter’s, but no one else’s. This is why she elects to ignore Ishigami’s clear infatuation with her from the beginning, pretending not to notice until the situation forces her to face it.
Though Yasuko’s daughter Misato is a minor character, she takes several crucial actions in the final third of the novel to develop the key moments of the plot. First, she notes Yasuko’s potentially reckless behavior in dating another man after Ishigami risked everything to save her. Second, in an “off-screen” moment that is recounted secondhand, she attempts to die by suicide, and this action implies that she feels a deep sense of guilt over her own involvement in Togashi’s death. The novel also suggests that this moment finally forces Yasuko to acknowledge the impact of her decisions, and in the closing scene, Yasuko takes responsibility for her own actions. However, the novel implicitly questions whether she makes the right decision, and the deleterious effect of her choice on Ishigami contributes to the author’s examination of The Morality of Love and Self-Sacrifice.
Shinji Togashi is Yasuko’s abusive ex-husband and the victim of the murder mystery at the center of the novel. However, he is a minor character whose only real contribution to the plot is his initial appearance and death. He was a successful businessman until he was caught embezzling company funds. After that, he developed an alcohol addiction and became violent, compelling Yasuko to divorce him. He is depicted as a cruel, selfish person who feels no shame or remorse about his abusive treatment of Yasuko or his veiled threats to Misato. After his death, the narrative does not expand on his character or background. In some mystery novels, the victim’s history becomes a crucial component to the investigation. In this case, however, as the final plot twist reveals, Togashi is not even the victim that the police are truly investigating, and this detail renders his appearance and characterization even less important. His sole purpose is to be the catalyst for the conflicts that follow his death.
Detective Shunpei Kusanagi is a police detective with the Tokyo Police, and the third of the three primary point-of-view characters. He is a major character who appears throughout the Detective Galileo series, both in the short stories and in the novels. He also has a junior detective partner named Kishitani.
Kusanagi is intelligent, observant, and intuitive. He can often sense when something is not quite right in a case, though he cannot always articulate why. When he encounters a particularly difficult case, he often turns to his friend, Yukawa, whom he has known since college.
Kusanagi is conscientious and believes in justice. In contrast with some of his colleagues, Kusanagi is determined to uncover the truth about Togashi’s death and Yasuko’s involvement, even when it would be easiest to simply accept Ishigami’s confession. He also values his friendship with Yukawa; this aspect of Kusanagi’s character is apparent in his concern over Yukawa’s emotional involvement in the case, and when he agrees to keep Yukawa’s deductions about Ishigami secret. However, the novel makes it clear that he would ultimately choose justice over his friendship if he were forced to; for example, he explicitly states that he will arrest Yasuko if she does not turn herself in, despite his promise to Yukawa.
Although he is the title character of the series, physicist Dr. Manabu Yukawa is not a point-of-view character in the novel and is arguably not even a primary character in the mystery plot. Instead, he comes in and out of the narrative, and his actions are viewed only from the perspectives of Ishigami, Yasuko, and Kusanagi. This narrative structure is common in the Detective Galileo series and is reminiscent of the Sherlock Holmes stories, which are told from the perspective of Holmes’s friend, John Watson. In fact, Yukawa is loosely modeled on the character of Sherlock Holmes; Holmes was a chemistry student at university in Doyle’s early stories, and this field is similar to Yukawa’s physics background. Additionally, Yukawa and Holmes share similar methods of observation and deductive reasoning, and both use scientific principles to investigate crimes. The novel also includes another Holmesian parallel in that Ishigami functions as a rival criminal of similar or superior genius to Yukawa, just as Holmes’s nemesis, James Moriarty, was intellectually equal or superior to Holmes.
Yukawa is a physics professor at Imperial University in Tokyo. He is described as attractive, with long, shoulder-length hair and wire-rim glasses. He has a brusque manner, particularly with his graduate students, but he also maintains close friendships with Kusanagi, and to an extent, Ishigami. He is well-read and knowledgeable in many subjects beyond science, including literature and history; by contrast, Ishigami only cares about math. Yukawa also has strong observational and analytical skills. However, as seen in his dealings with Ishigami, he does not conform to the same strict code of legal justice that Kusanagi uses. For Yukawa, justice and truth are not binary opposites. For instance, he believes that Yasuko should be permitted to get away with her crime so that Ishigami can fulfill his wish to protect her. Simultaneously, he believes that each person has inherent value, regardless of their individual circumstances. He therefore believes that Ishigami’s actions are unforgivable and deserve punishment. In this way, Yukawa’s stance and actions contribute to the themes of The Inherent Worth of Individuals and Navigating Imperfect Justice and Moral Ambiguity.



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