Proper Japanese Title: 男一匹ガキ大将
Originally serialized in Weekly Shonen Jump, the series is generally considered the biggest hit of the magazine's early era and helped establish the magazine as the major hit it would later become. The series itself inspired other young creators like Masami Kurumada to get into creating manga and help the magazine reach new levels of popularity in subsequent decades (both Kurumada and Tetsuo Hara would later serialize their own tribute series to this one in Weekly Shonen Jump, though neither were successful in comparison to their better-known serials).
Alongside Harenchi Gakuen and Chichi no Tamashii, it was one of the debut series that launched the Jump Comics line of tankobons in late 1969 (a brand that has gone on to produce many of the best-selling manga of all time). By virtue of outlasting those two series, when it ended at twenty volumes in 1973, it was the longest Jump Comics series until it was surpassed in 1975 by Dokonjō Gaeru.
It was the debut serial of Hiroshi Motomiya, who was only in his early 20's, and had previously worked a few years in the rental manga industry (publishing his earliest works with Hinomaru Bunko). Notably, because the series was so popular and significant to the young magazine, it lasted longer than the author had wanted and he was forced by editorial to continue beyond his intended ending.
In the context of the magazine itself, in 1970 and 1971, it was common for Gaki-Daishō to get the front cover three or four issues in a row, so when the series "ended" in late 1971 and Motomiya began his second serial Musashi (which was also published in Weekly Shonen Jump), the cover treatment continued for a few weeks of the new series (getting the cover for three of its first five chapters). But, by chapter seven, Motomiya was already having to release new chapters of Gaki-Daishō alongside Musashi.
Three special chapters of Gaki-Daishō were published while Musashi was ongoing and each one got the cover and was the first chapter in the issue (while Musashi was much further back) and apart from a shared cover with Gaki-Daishō (for chapter seven) and one with Isamu (chapter nine), Musashi never got the cover again and ended after twenty-five chapters. Only two issues later, Gaki-Daishō returned and once again was the most heavily featured series in the magazine for the next few months, only ending for real in early 1973 after over 150 chapters.
A few months later Motomiya would return with his next series (which lasted nearly 100 chapters) and he would go on to remain one of the major creators of the magazine through the 70's and into the 80's (before fully changing his focus to seinen manga) but Otoko Ippiki Gaki-Daishō has remained his most popular and defining shonen series (and excluding sequels, it remains his second longest single series after Salaryman Kintarō).
However, due to the circumstances of the final volumes of the series being a result of editorial push, they are not reprinted in modern editions of the series (such as the bunkoban edition) and even retail digital volumes of the series stop well before the originally published conclusion. Though it never sold as much as many of the better-known series from Shonen Jump's Golden Age (where circulation peaked at over 6 million), it still has a legacy as an early classic and has been promoted in later decades of the magazine, such as on covers in honor of the 40th and 50th anniversaries.
The plot of the series revolves around Mankichi Togawa, who at the start of the series is a single delinquent student with one dedicated follower (Rappa) who blows a trumpet to kick off the fights Mankichi gets into. Like many later iconic shonen protagonists, Mankichi's power is his ability to appeal to the others around him who join his cause (sometimes only after first losing to him in a fight).
Through the series his followers grow to eventually become such a huge amount they become a literal army of thousands that performs impressive feats of strength and engage in all-out war. While Rappa is too young to properly take part in much of the action in the series, Mankichi's most prominent and consistent follower is Ginji Kubo (a young delinquent with an eyepatch).
The villains of the series are at times other delinquents but also include much larger enemies in the form of big business or an arc where Mankichi was sent to a juvenile delinquent rehabilitation facility (which had the atmosphere and harshness of a prison). Some of Mankichi's closest friends die along the way (with one former enemy who became his follower heroically dying to save him) and Mankichi himself completely loses his way at times (with his friends trying to revitalize his spirit). The series also included romance in the form of Mankichi's first love Tomoko and him briefly leaving her for for another girl (Ayumi) while she waited for him to return to her (which he eventually did).