Historical Model:
There is no historical figure Ôboshi Yuranosuke, as the name is meant to be nothing more than an all-too-obvious alias for Ôishi Kuranosuke, the chief retainer (kar?) of Asano Naganori. Ôishi learned of his lord's death and several days after the fact while he was in residence in Ak? castle, which was a considerable distance from Kamakura. Ôishi's initial response to this news was to forgo any drastic action in favor of calmly accepting the verdict of the court regarding the confiscation of Asano lands and petitioning for the instatement of Asano's younger brother, Daigaku, as the new head of the family. This course of action was in direct conflict with the views of some of his retainers who strongly urged an immediate attack on Kira. (Many of these more extreme individuals lived with Kamakura, and it is likely that they were strongly influenced by public opinion and the surrounding samurai community.) It was only after all bureaucratic channels were exhausted that Ôishi committed himself and the men that followed him to a course of revenge. After the successful attack on Kira's mansion, Ôishi took Kira's head and placed it before his master's grave at Sengakuji Temple, where he and the other r?nin then waited for officials from the shogunate to arrest them. A huge debate erupted over the virtue of the r?nin actions - they showed loyalty and samurai spirit but displayed a flagrant disregard of the laws of the land - and it was not until 3 months later, on the anniversary of their lord's death, that they were sentenced to commit seppuku.

There is evidence that Ôishi moved to Yamashina following the surrender of Ak? castle. Similar to the Ch?shingura account, he separated from his wife and, while frequenting the pleasure quarters, took up residence with a mistress by the name of Okaru.

Taiheiki Model:
There is no Ôboshi Yuranosuke in the Taiheiki, nor is there any obvious counterpart.

Other Literary Models: (see appendix for plot details)
Ôboshi Yuranosuke (Goban taiheiki)
Ôkishi Kunai (Oni kage musashi abumi)
Ôkishi Yuranosuke (Ch?shin kogane tanzaku)

Yuranosuke's character in Ch?shingura is a distillation of the popular conception of Ôishi at the time, and his actions are, for the most part, adaptations of both what Ôishi was known to have done between 1701 and 1703, and what ?ishi's counterparts had done in earlier adaptations of the event.

Yuranosuke is, without a doubt, the hero of Ch?shingura and the loyalty he stands for serves as a moral beacon that guides the outcome of the individual events, as well as the ultimate climax, of the play. He stands in stark contrast to the evil and morally repugnant Moronao, and, with his moral fiber colored with such a particular hue, even exists as someone distinctly different than Honz?, whose samurai virtue is marred by his predilection for pragmatism, as evinced by his 'bribery' of Moronao. Yuranosuke is self-righteous, virtually omniscient and can exercise complete self-control no matter the circumstances; during his display of dissipation in act seven, the reader is never lead to believe that there is any struggle with his lifestyle or crack in his motivational fa?ade. Indeed, Yuranosuke is so 'good' and so lacking in internal conflict - his only mistake is to refuse Kanpei's initial contribution to their cause - that he suffers from the same one-dimensionality as Moronao, a fact that deters from his reception by modern audiences and likely explains the trend towards expressing a more 'realistic,' human side to Kuranosuke in more recent adaptations of the Ak? incident (see Genroku ch?shingura by Mayama Seika).

Despite Yuranosuke's central importance to the over-all plot of Ch?shingura, he spends relatively little time on stage aside from his major appearances in acts four and seven. This, however, in no way hinders his overwhelming effect on the action throughout the play. In scenes where he makes even a brief appearance, Yuranosuke often serves as an agent that brings about abrupt plot developments: In act four, his sudden entrance while Enya is dying allows the vendetta to take place; in act nine, he appears in time to allow Honz? to explain his motivation and pass on the map of Moronao's mansion; and in act ten, he leaps out of the box to prevent the loyal Gihei from killing himself and his son.