Some TMNT stuff really isn't for little kids.
Set primarily at the beginning of Edo period of Japan (early 17th century), with anthropomorphic animals replacing humans, it features a rabbit rōnin, Miyamoto Usagi, who is partially based on the famous swordsman Miyamoto Musashi. Usagi wanders the land on a musha shugyō (warrior's pilgrimage) occasionally selling his services as a bodyguard (用心棒／ようじんぼう yōjinbō is Japanese for "bodyguard"). Usagi Yojimbo is heavily influenced by Japanese cinema and has included references to the work of Akira Kurosawa (the title of the series is derived from Kurosawa's 1960 film Yojimbo) and to icons of popular Japanese cinema such as Lone Wolf and Cub, Zatoichi, and Godzilla. The series is also influenced somewhat by Groo the Wanderer by Sergio Aragonés (Sakai is the letterer for that series), but the overall tone of Usagi Yojimbo is typically less comedic.
The books consist of short stories, and occasionally novel-length stories, with underlying larger plot-lines which culminate in long extended story lines. The stories include many references to Japanese history and Japanese folklore, and sometimes include mythical creatures. The architecture, clothes, weapons, and other objects are drawn with a faithfulness to the period's style. There are often stories whose purpose is to illustrate various elements of Japanese arts and crafts, such as the fashioning of kites, swords, and pottery. Those efforts have been successful enough for the series to be awarded a Parents' Choice Award in 1990 for its educational value through Stan's "skillful weaving of facts and legends into his work." The series also follows the standard traditional Japanese naming convention for all featured characters: their family names followed by their given names. Usagi was named the thirty-first greatest comic book character by Empire Magazine.
Originally, Usagi and other characters in the series were going to be human in stories explicitly modeled after the life of Miyamoto Musashi. However when Sakai was idly doodling, he drew rabbit ears tied in a topknot on his proposed hero and was inspired by the distinctive image it gave him. Usagi was first conceived as a supporting character in The Adventures of Nilson Groundthumper and Hermy, a brief series that predates Usagi Yojimbo. Sakai quickly expanded on the idea and his story world quickly took on an anthropomorphized cartoonish nature which created a fantasy setting he decided suited his dramatic needs well with a unique look he thought could attract readers.
Usagi first appeared in the anthology Albedo Anthropomorphics in 1984, and later in the Fantagraphics Books anthropomorphic anthology Critters, before appearing in his own series in 1987. The Usagi Yojimbo series has been published by three different companies. The first publisher was Fantagraphics (volume one; 38 regular issues, plus one Summer Special and three Color Specials). The second was Mirage Comics (volume two; 16 issues). The third is Dark Horse Comics, at which Usagi Yojimbo is still being published (as volume three, over 100 issues), and who also released a fourth Color Special. A fourth publisher, Radio Comix, has published two issues of The Art of Usagi Yojimbo which contained a selection of unpublished drawings, convention sketches, and other miscellaneous Usagi Yojimbo artwork. The first issue also included an original Usagi Yojimbo short story. In 2004, Dark Horse Comics published a Twentieth Anniversary hardcover volume also entitled The Art of Usagi Yojimbo.
Because Usagi Yojimbo is a creator-owned comic and Stan Sakai has complete and sole ownership of the character, Miyamoto Usagi has been able to appear in occasional short stories published by companies other than the one currently publishing his series. Usagi has appeared in stories published by Cartoon Books, Oni Press, Sky Dog Press, Wizard Press, and most recently in the benefit book Drawing the Line, the proceeds of which went to Princess Margaret Hospital and The Hospital for Sick Children, both in Toronto, for cancer research.
Stan Sakai has also been able to experiment with formats for Usagi Yojimbo, such as when he published the color story "Green Persimmon" originally as twelve separate 2-page chapters serialized in Diamond Comic Distributor's monthly catalog "Previews." He has also serialized two short stories in a comic strip format in the tabloid size promotional publication Dark Horse Extra. With Usagi Yojimbo stories ranging in length from single page "gag" stories to multi-issue "epic" adventures, Stan Sakai has proven himself a master of sequential story-telling.
Usagi has also appeared several times in Teenage Mutant Ninja Turtles (the comic, both of the animated serie, and the toy line), and the Turtles have appeared in Usagi Yojimbo as well. In his guest appearances, he is closest to Leonardo, both sharing the same ideals and code of ethics.
In addition, Sakai created a limited spin off series called Space Usagi that featured characters similar to those in the original series, including a descendant of Miyamoto Usagi, but set in a futuristic setting that also emulated Feudal Japan in political and stylistic ways. A cartoon series based on Space Usagi was planned, but aside from a short pilot, nothing came of it. 
Two editions of an Usagi role-playing game have been made, a 1998 version from Gold Rush Games and a 2005 version from Sanguine Productions.
There was also a computer game called Samurai Warrior: The Battles of Usagi Yojimbo released for the Commodore 64, ZX Spectrum and Amstrad CPC platforms in 1988, by the now defunct computer game label Firebird. More recently, the game Way of the Ronin was released for mobile platforms. 
There was a motion comic based on the short story A Life of Mush , and a stop-motion short film called The Last Request, which convinced Sakai to approve an Usagi feature from its producers, Lintika Films. 
There was also been a stage play produced by the Southwark Playhouse in London. 
The series has been awarded 3 Eisner awards.
- 1996 Eisner Award for "Best Letterer" (along with Sergio Aragonés and Mark Evanier's Groo the Wanderer)
- 1996 Eisner Award for "Talent Deserving of Wider Recognition"
- 1999 Eisner Award for "Best Serialized Story" ("Grasscutter")
And around 20 nominations.
Several of the characters in Usagi's world are inspired by or make reference to samurai movies. Usagi's former lord is named Mifune, which is a nod to Toshirō Mifune, an actor who starred in countless classic Samurai films. Gen, the rhino bounty hunter, was inspired by the characters made famous by Toshirō Mifune in the samurai films Yojimbo and Sanjuro. Zato-Ino, the Blind Swordspig, is a reference and tribute to the film character of Zatoichi. The story arc "Lone Goat and Kid" features an assassin who wanders with his son in a babycart, referring to the film/manga series, Lone Wolf and Cub. Most significantly, the main character's name, Miyamoto Usagi, is a play on "Miyamoto Musashi", Japan's most famous historical samurai and the author of The Book of Five Rings, and "Usagi" the Japanese language word for "rabbit" (Also, the story notes for one volume cite Hiroshi Inagaki's Samurai Trilogy, which features Miyamoto Musashi as a protagonist, as an influence). His friend Tomoe Ame, a feline samurai, is inspired by the female samurai Tomoe Gozen. The storyline "The Dragon Bellow Conspiracy" includes elements reminiscent of the classic Akira Kurosawa films The Seven Samurai and The Hidden Fortress, particularly the way that Usagi collects various allies to raid an evil lord's fortress.
While Usagi Yojimbo draws most heavily upon samurai and chanbara films, it has also been influenced by Japanese films from other genres. For example, the three-part story "Sumi-E" (included in Vol. 18. Travels with Jotaro) features monsters resembling Godzilla (identified as "Zylla," who was first introduced in Vol. 2. Samurai), Gamera, Ghidorah, Mothra, and Daimajin.
Books 1-7 are published by Fantagraphics Books; Books 8+ are published by Dark Horse Comics. Hardcover versions of the Dark Horse collections often include exclusive extras; some of this material was included in the 2004 artbook, also published by Dark Horse.
- Book 1: The Ronin
(Collects appearances in Albedo 2-4; The Doomsday Squad 3; Critters 1, 3, 6-7, 10-11, 14; and the Usagi Yojimbo Summer Special, HC: ISBN 1560971320 ; TPB: ISBN 0930193350)
- Book 2: Samurai
(Collects Fantagraphics issues 1-6, HC: ISBN 156097074X ; TPB: ISBN 0930193881)
- Book 3: Wanderer's Road
(Collects Fantagraphics issues 7-12 and “Turtle Soup”)
- Book 4: Dragon Bellow Conspiracy
(Collects Fantagraphics issues 13-18)
- Book 5: Lone Goat and Kid
(Collects Fantagraphics issues 19-24)
- Book 6: Circles
(Collects Fantagraphics issues 25-31, and story from Critters #50)
- Book 7: Gen's Story
(Collects Fantagraphics issues 32-38 and story from Critters #38)
- Book 8: Shades of Death
(Collects Mirage issues 1-6 and backup stories from 7-8)
- Book 9: Daisho
(Collects Mirage issues 7-12, 14)
- Book 10: The Brink of Life and Death
(Collects Mirage issues 13, 15-16 and Dark Horse issues 1-6)
- Book 11: Seasons
(Collects Dark Horse issues 7-12, "Green Persimmon" from Diamond Previews, and combines "Hebi" from the hardcover edition of book 7 with "Courage of the Plum" from the "Art of Usagi Yojimbo" 1 into a single story called "Snakes and Blossoms" with a new framing sequence)
- Book 12: Grasscutter
(Collects Dark Horse issues 13-22)
- Book 13: Grey Shadows
(Collects Dark Horse issues 23-30)
- Book 14: Demon Mask
(Collects Dark Horse issues 31-38, and stories from Dark Horse Presents 140 & Annual 1999; Wizard 97; Oni Double Feature 10; and Dark Horse Extra 20-23)
- Book 15: Grasscutter II: Journey To Atsuta Shrine
(Collects Dark Horse issues 39-45)
- Book 16: The Shrouded Moon
(Collects Dark Horse issues 46-52)
- Book 17: Duel at Kitanoji
(Collects Dark Horse issues 53-60)
- Book 18: Travels with Jotaro
(Collects Dark Horse issues 61-68)
- Book 19: Fathers and Sons
(Collects Dark Horse issues 69-75)
- Book 20: Glimpses of Death
(Collects Dark Horse issues 76-82, and a short story from Drawing the Line)
- Book 21: The Mother of Mountains
(Collects Dark Horse issues 83-89)
- Book 22: Tomoe's Story
(Collects Dark Horse Issues 90-93 and Usagi Yojimbo Color Specials 1-3)
- Book 23: Bridge of Tears
(Collects Dark Horse issues 94-102)
- Book 24: Return of the Black Soul
(Collects Dark Horse issues 103-109 and Usagi Yojimbo FCBD 2009)
- Book 25: Fox Hunt
(Collects Dark Horse issues 110–116 and "Saya" from MDHP 18)
- Book 26: Traitors of the Earth
(Collects Dark Horse issues 117-123, "Usagi and the Kami of the Pond" from Dark Horse Maverick 2001, and "Cut the Plum" from MDHP 35)
- Book 27: A Town Called Hell
(Collects Dark Horse issues 124-131)
- Book 28: The Red Scorpion
(Collects Dark Horse issues 132-138)
- Space Usagi
(Collects the Space Usagi 3-issue miniseries "Warrior," "Death & Honor," and "White Star Rising;" and stories from Teenage Mutant Ninja Turtles 47 and Usagi Color Special 3)
- The Art of Usagi Yojimbo: 20th Anniversary Edition, published 2004.
- Usagi Yojimbo: Yokai
(The first Usagi Yojimbo original graphic novel. A fully painted self-contained story released to celebrate Usagi Yojimbo's 25th anniversary.)
- Usagi Yojimbo: The Special Edition
(Collects Usagi Yojimbo books 1 to 7, will be published by Fantagraphics in December 2010)
- The Usagi Yojimbo Saga Volume 1
(Collects Usagi Yojimbo books 8 to 10, to be published in both limited hardcover and softcover omnibus editions by Dark Horse in October 2014)
- The Usagi Yojimbo Saga Volume 2
(Collects Usagi Yojimbo books 11 to 13, to be published in both limited hardcover and softcover omnibus editions by Dark Horse in March 2015)
- The Usagi Yojimbo Saga Volume 3
(Collects Usagi Yojimbo books 14 to 16, to be published in both limited hardcover and softcover omnibus editions by Dark Horse in May 2015)
- Solomon, Charles. "Don't get between the rabbit and his sword", The Los Angeles Times, 2005-11-25. Retrieved on 2010-11-28.
- Solomon, Charles. "Take one part Toshiro Mifune. Then add adventure and humor to get artist Stan Sakai's 'Usagi Yojimbo.'", The Los Angeles Times, 1993-03-08. Retrieved on 2010-11-28.
- Dobashi, Mas (1997-02-24). Stan Sakai Interview. usagiyojimbo.com (originally Tozai Times, Vol. 13 Issue 148. Retrieved on January 21, 2008.
- Empire | The 50 Greatest Comic Book Characters
- Usagi Yojimbo Dojo - FAQ: Questions about Usagi Yojimbo
- Usagi Yojimbo Dojo - FAQ: Questions about Nilson Groundthumper and Hermy
- "WC: 25 YEARS OF USAGI YOJIMBO", Comic Book Resources. Retrieved on 2010-11-28.
- "25 YEARS OF "USAGI YOJIMBO"", Comic Book Resources. Retrieved on 2010-11-28.
- HC : hard cover
- TPB : trade paperback