Bakumatsu Kikansetsu Irohanihoheto
English title: Intrigue in the Bakumatsu: Irohanihoheto
Japanese title: 幕末機関説 いろはにほへと
Type: ONA
Source: Original
Episodes: 26
Status: Finished Airing
Aired: Oct 6, 2006 to Apr 6, 2007
Duration: 24 min per ep
Rating: PG-13 - Teens 13 or older
Studios: Sunrise
Producers: Bandai Visual
Licensors: Sentai Filmworks
Genres: Action, Drama
Themes: Historical, Samurai

In the final years of the Bakumatsu, wandering mercenary Yojiro Akizuki travels the length and breadth of Japan. And while he employs his sword in the usual fashion, he also uses it to help him locate supernatural items which he pursues with single-minded determination, often with bloody results. In the course of his quest, he crosses paths with a traveling theater group whose members have their own dark agenda. Is it a chance meeting or the result of some, as yet, undiscovered conspiracy? 

(Source: Sentai Filmworks)

The series was broadcast on the japanese video on demand service GyaO.