is a Japanese mystery light novel series written by Nanako Tsujimura and illustrated by Utako Yukihiro. Shueisha has published fourteen main volumes from December 2015 to November 2025 under their Shueisha Orange Bunko imprint, as well as three collections of short stories. A manga adaptation with art by Mika Akatsuki has been serialized in Ichijinsha's manga magazine Monthly Comic Zero Sum since November 2019. An anime television series adaptation by Shuka aired from January to March 2020.
Plot
Volume One Seigi Nakata runs across a beautiful foreign man named Richard Ranasinghe de Vulpian being attacked by drunkards near Yoyogi Park on his way home late at night from his job as a security guard. He rushes to Richard's rescue and joins him at the police station, where Richard reveals that he is an Englishman working in Japan as a jeweler. Seigi then brings a ring he inherited from his grandmother to Richard in hopes of having the gemstone identified. Richard informs him that the ring was stolen many decades ago. Seigi asks Richard to help him find the owner. By a twist of fate, Richard is already acquainted with the owner and brings Seigi to see her. There, the woman listens to the story of Seigi's poor pickpocket grandmother and returns the ring to him with her blessing.
Following this adventure, Richard offers Seigi a job at his jewelry shop and Seigi happily accepts and begins his employment under Richard. The rest of the first volume slowly introduces Seigi to the world of gemology, where he learns about mineral names for gemstones and what customers are looking for in gems, including cases where he's introduced to a lesbian woman using a ruby as a way to decide her future, a bartender trying to protect his hostess girlfriend from alcoholism, and a widower unsure of what to do with his late wife's engagement ring.
The book ends with Seigi turning down an internship at another company, saying he prefers to work with Richard, as he rather likes his boss.
Volume Two
The second volume of the series begins to delve deeper into the darker side of the gemstone industry. It includes an elementary school student hoping a gemstone can protect his family and a woman trying to cope with a breakup by buying herself a garnet ring before delving into more the darker stores.
The titular "Emerald" case opens with Richard being asked to solve a possible haunting related to an emerald necklace, and after Seigi ropes him into helping, he instead uncovers a drug trafficking ploy using emeralds as payment and smuggling them across continents via the rental of ballet costumes. Richard ends up having to make multiple statements to the DEA before he and Seigi attend a ballet performance together.
Following that, Seigi meets by chance an old friend and clubmate from his karate days and winds up discovering the friend and protector he admired has wound up taking advantage of a woman with dementia and trying to sell her treasured fire opal. The story ends with Seigi's old friend declaring he never wants to see Seigi again, as someone like Seigi can't understand how someone could fall so far. Seigi then cries in Richard's car while Richard comforts him.
Volume Three During volume three cases, it becomes quickly apparent Richard is not acting entirely himself. While he manages the first case, Topaz, relatively normally, in the following case, Turquoise, he takes on the alias "Edward Baxter" and barges into a jewelry scam shop to scam them back and terrify them into hiding.
While Richard refuses to explain any of these actions, during the auction in the Jade case, he is confronted by a fellow jeweler working on behalf of foreign clients to purchase a particular carved jadeite item. He refers to Richard as "Lord Claremont" and warns Seigi from working with Richard, and that Richard is only using him and Richard's own beauty for his own purposes and does not care about anyone else. Seigi refuses to listen to the man, and Richard only explains that various things happened with his wealthy family back in England.
When Seigi's friend Tanimoto is deciding whether or not to pursue and engagement in the following case, and he is accordingly deciding whether or not to confess his own romantic feelings to her, Richard tells a story about himself as if it's another person, detailing a former engagement broken off for monetary reasons. When he finally convinces Seigi to pursue Tanimoto, he vanishes without a word, leaving only a cryptic note on his shop that it will be closed until further notice.
Once Seigi handles the situation with Tanimoto and they both remain single, he discovers the note and Richard's phone disconnected, where the book ends on a cliffhanger.
Structure The series is organized into three distinct arcs, each marked by a time skip and with distinct narrative styles. The first arc encompasses the first six volumes. Each are divided into four distinct cases each named after a gemstone and featuring specific customers, with a bonus case matching the format but much shorter at the end. They are told almost exclusively from Seigi's first-person perspective.
After a two-year time skip between volumes six and seven, the novel format changes for volumes seven to 10 to add a short prologue from Richard's voice in first person before returning to Seigi, and each book is divided into chapters covering days instead of distinct short stories or novellas involving specific gems and customers. The novels in arc two are much more holistic stories.
After another three year time skip, volume 11 picks up with a short prologue from Seigi and then follows a new narrator named Minoru in third person. The case format is back, but no longer named after gemstones but characters. Seigi also receives a short "half case" to narrate at the end focusing on himself and Richard.
Characters
An English jeweler with customers worldwide, Richard is an androgynous beauty who Seigi likens to a “living jewel.” He was born and raised in England by his aunt and uncle, spending summers visiting Provence, France to see his French mother, Catherine. He was privately tutored as a young child and then attended a boarding school in Switzerland before beginning his studies at Cambridge. Richard is a polyglot who speaks fluent Japanese even better than some native Japanese speakers and at least a dozen other languages across the novels. Before becoming a jeweler, he intended to become an English teacher to foreign speakers. He was taught Japanese from a young age and took a vested interest in the country and culture. He is incredibly picky when it comes to milk tea and carries around his own tea leaves from Sri Lanka in a tin to make it. He also has a strong sweet tooth and eats sweets more often than more typical savory meals and is easily bribed with candies and desserts. He offers Seigi a part-time job when opening his jewelry store "Jewelry Etranger" in Ginza.
Seigi begins the series as a university student at Kasaba University, hoping to become a public servant in order to repay his mother for her investment in him. He was very attached to his grandmother as a child, who gave him the strong sense of justice implied by his name, which means "justice" in Japanese. He has been teased for his name in the past. Seigi is friendly and honest to a fault. While Richard finds these traits endearing, it's sometimes hard for him tell what Seigi's intentions are. Seigi has post traumatic stress disorder owing to a childhood filled with domestic violence on the part of his abusive father and fears becoming like him. He was enrolled in karate to deal with his anger issues as a child, and later takes up therapy for the same issues when he suffers a relapse. He is skilled at household chores as a whole, and his specialty is pudding.
One of Seigi's classmates in college. She is very knowledgeable on mineralogy, having studied it in high school and often provides Seigi insight on the subject. Seigi has feelings for her, but has a hard time admitting them. Tanimoto, however, is asexual and aromantic and they settle into a close platonic relationship as the series progresses. She has an interest in teaching science to young middle school students.
One of Seigi's friends from college. His role differs dramatically between the novels and anime, as his original appearances were adapted out and his character replaced other minor figures from Seigi's college. He is quite supportive of Seigi's pursuits and is one of Seigi's only former classmates to understand Seigi's desire to live outside typical expectations. He is heavily interested in music. In volume 5, he quits college to move to Spain in order to pursue flamenco guitar and music as a career. As of volume 10, he appears to have been successful. Seigi recommends him as a Japanese tutor for Henry and they begin a fast friendship, despite Henry using the alias "Enrique Wabisabi." When Henry admits the ruse, Shimomura does not fully understand the confession in English, but happily greets his friend in person for the first time with a hug.
Jeffrey is Richard's elder cousin on his father's side and was raised with him like a brother. Until Richard was in college, he considered Jeffrey to be the most important person in his life. Jeffrey supports Richard and Seigi through both financial means and investigative information. He also gives Seigi advice on becoming Richard's secretary.
Henry is Richard's elder cousin and Jeffrey's older brother. He favors the piano, and is the only Claremont to not speak Japanese on his introduction, although he does pick it up later. During Richard's college years, he suffered an illness that still affects him years later. He becomes the tenth Earl Claremont after the death of his father.
Saul is a Sri Lankan man who serves as Richard's mentor and boss. He gave his last name to Richard for use after helping Richard recover from past trauma.
Media Light novel In the initial Seven Seas Entertainment translation of volume 6, a chapter was omitted. After the issue was brought to the attention of Tsujimura, Seven Seas Entertainment apologized for this error on Twitter and offered a reprinted version with the chapter, pushing back the release of the print version several months.
+Volume listNo.Japanese titleEnglish titleRelease dateEnglish release date1宝石商リチャード氏の謎鑑定The Case Files of Jeweler RichardDecember 17, 2015October 11, 20222宝石商リチャード氏の謎鑑定 エメラルドは踊るThe Case Files of Jeweler Richard: The Dancing EmeraldsMay 20, 2016December 6, 20223宝石商リチャード氏の謎鑑定 天使のアクアマリン The Case Files of Jeweler Richard: The Angel's AquamarineNovember 18, 2016February 28, 20234宝石商リチャード氏の謎鑑定 導きのラピスラズリThe Case Files of Jeweler Richard: The Lapis Lazuli of GuidanceFebruary 17, 2017May 9, 20235宝石商リチャード氏の謎鑑定 祝福のペリドットThe Case Files of Jeweler Richard:: The Peridot of RemembranceAugust 22, 2017August 1, 20236宝石商リチャード氏の謎鑑定 転生のタンザナイトThe Case Files of Jeweler Richard: The Tanzanite of RebirthJanuary 19, 2018January 16, 20247宝石商リチャード氏の謎鑑定 紅宝石（ルビー）の女王と裏切りの海June 21, 2018March 5, 20248宝石商リチャード氏の謎鑑定 夏の庭と黄金（ドール）の愛December 18, 2018July 16, 20249宝石商リチャード氏の謎鑑定 邂逅の珊瑚（サーンウー）August 21, 2019November 19, 2024 宝石商リチャード氏の謎鑑定公式ファンブック エトランジェの宝石箱November 26, 201910宝石商リチャード氏の謎鑑定 久遠の琥珀June 19, 2020April 22, 202511宝石商リチャード氏の謎鑑定 輝きのかけらJune 18, 2021 December 30, 202512宝石商リチャード氏の謎鑑定少年と螺鈿箪笥June 24, 2022July 28, 202613宝石商リチャード氏の謎鑑定 ガラスの仮面舞踏会October 19, 202314宝石商リチャード氏の謎鑑定再開のインコンパラブルSeptember 19, 202415宝石商リチャード氏の謎鑑定比翼のマグル・ガルNovember 19, 2025宝石商リチャード氏の謎鑑定エトランジェの宝箱November 19, 2025
Manga A manga adaptation illustrated by Mika Akatsuki began serialization in Ichijinsha's Monthly Comic Zero Sum magazine on November 26, 2019. The manga is licensed in English by Seven Seas Entertainment.
Anime