| 1 | | | The Three-Fingered Man |
| | Eizo | Inoue | Narrator's friend. |
| | John Dickson | Carr | American author. |
| | | | Koto - traditional Japanese string instrument |
| | Kenzo | Ichiyanagi | The current master of the house of Ichiyanagi. |
| 2 | | | The Descendants of the Honjin |
| | | | Honjin - an inn |
| | Itoko | | Kenzo's mother. |
| | Taeko | | Itoko's elder daughter. |
| | Ryuji | | Itoko's second son. |
| | Saburo | | Itoko's son. |
| | Suzuko | | Itoko's youngest daughter. |
| | Ryosuke | | Kenzo's a cousin. |
| | Akiko | | Ryosuke's wife. |
| | Katsuko | Kubo | Kenzo's fiancé. |
| | Rinkichi | Kubo | Katsuko's father. |
| | Tama | | Suzuko's pet kitten. |
| 3 | | | The Sound of a Koto |
| | | | Kamishimo - the formal dress of the samurai |
| | Ginzo | Kubo | Katsuko's uncle. |
| | Old Nao | | Kenzo's cook. |
| | Kiyo | | Itoko's maid. |
| | Ihei | | Kenzo's great-uncle. |
| 4 | | | A Great Tragedy |
| | Genshichi | | One of Kenzo's servants. |
| | Shokichi | | One of Kenzo's servants. |
| 5 | | | A New Use for a Koto Pick |
| | | Isokawa | Chief investigator. |
| | Kosuke | Kindaichi | Private detective. |
| 6 | | | A Sickle and a Koto Bridge |
| | | Kimura | Detective sergeant. |
| 7 | | | A Strategy Meeting |
| | Ofuyu | | Kenzo's lady friend. |
| | Yosuke | Taguchi | A farmer. |
| | Seno | | Insurance company agent. |
| 8 | | | Kosuke Kindaichi |
| | A.A. | Milne | British author. |
| | Antony | Gillingham | Lead character in a detective novel. |
| | Sakue | | Kenzo's father. |
| | Hayato | Ichiyanagi | Sakue's younger brother. |
| 9 | | | The Cat's Grave |
| | Arthur | Conan Doyle | British writer. |
| | Maurice | Leblanc | French novelist. |
| | Ruiko | Kuroiwa | Japanese journalist. |
| | Edogawa | Ranpo | Japanese author. |
| | Fuboku | Kozakai | Novelist. |
| | Saburo | Koga | The main character from the classic Japanese fantasy Suwa Engi. |
| | Udaru | Oshita | Detective story writer. |
| | Takataro | Kigi | Novelist. |
| | Juza | Unno | Japanese fiction writer. |
| | Mushitaro | Oguri | Japanese author. |
| | Ellery | Queen | Novelist. |
| | Freeman | Wills Crofts | Irish author. |
| | Agatha | Christie | English writer. |
| 11 | | | Two Letters |
| | Shizuko | Shiraki | Katsuko's friend. |
| | Shozo | Taya | Katsuko's ex-boyfriend. Aka: T. |
| 17 | | | The Accidental Locked Room |
| | Kyokichi | Shimizu | The three-fingered man. |
