How accurate is Kingdom to real history?
The framework is accurate. The sequence of wars, the states involved, the major generals on each side and the outcomes of the great campaigns all follow the Shiji and the standard historical understanding of the unification wars. A reader who knows Kingdom's map knows the real map of 230 BC China in outline.
The texture is invented. The Shiji rarely describes how battles felt, what generals said to each other or how individual soldiers lived, so Hara builds duels, rivalries and speeches to carry the record's facts. Shin's Hi Shin Unit is a fictional formation wrapped around the real Li Xin, whose recorded career gives only a skeleton.
Some figures are deliberate reworkings. The manga's Houken, a near supernatural warrior, dramatizes a recorded Zhao general, Pang Nuan, into a force of nature for thematic reasons. Other characters are composites, and a few historical figures receive changed genders, family ties or timelines to serve the story's structure, changes Japanese guidebooks and fan references document carefully.
Chronology is compressed where the record is thin. Years of maneuvering can become a single campaign season, and separate recorded incidents are sometimes merged. Historians who comment on the series generally treat it as responsible popular history: wrong in details it never claimed, right in the structure it teaches.
The accuracy question is finally about respect for the source. Hara has said the recorded outcomes are fixed points he will not overturn, which makes Kingdom a dramatization rather than an alternate history, and that promise is why history minded readers in Japan use the manga as a gateway to the Shiji itself.
