The Age 37 Series is the sixth part of Kindaichi Case Files. It started in 2018 with the Uta Island Resort Murder Case and put on hiatus in 2021 with the Murderer With Twenty Faces. It restarted in 2023 with the Werewolf Game Murder Case.
| CaseNumber | Case Name | First ChapterReleased Date | Last ChapterReleased Date | Length | Series | AnimeAdaptation |
| 1 | Uta Island Resort Murder Case | January 23, 2018 | August 28, 2018 | 15 Chapters | Kindaichi 37 Years Old Case Files | 
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| 2 | Tower Mansion Madam Murder Case | September 11, 2018 | January 22, 2019 | 10 Chapters | Kindaichi 37 Years Old Case Files |
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| 3 | Kyoto Beauty Florist Murder Case | February 12, 2019 | August 27, 2019 | 14 Chapters | Kindaichi 37 Years Old Case Files |
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| 4 | Hakodate Western-style Hotel, The New Murder | September 10, 2019 | March 24, 2020 | 14 Chapters | Kindaichi 37 Years Old Case Files |
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| 5 | Poltergeist Mansion Murder Case | April 14, 2020 | October 13, 2020 | 13 Chapters | Kindaichi 37 Years Old Case Files |
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| 6 | Ayase Serial Murder Case | October 27, 2020 | June 8, 2021 | 16 Chapters | Kindaichi 37 Years Old Case Files |
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| 7 | Murderer With Twenty Faces | June 22, 2021 | January 11, 2022 | 14 Chapters | Kindaichi 37 Years Old Case Files |
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| 8 | Werewolf Game Murder Case | April 26, 2023 | November 29, 2023 | 15 Chapters | Kindaichi 37 Year Old Case Files |
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| 9 | Headless Skier Case | January 10, 2024 | July 24, 2024 | 13 Chapters | Kindaichi 37 Year Old Case Files |
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| 10 | Otowa Black PR Murder Case | August 14, 2024 | TBA | TBA Chapters | Kindaichi 37 Year Old Case Files |
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