Jomon is widely regarded as the “original” Shiba Inu among the four main native lineages—Sanin, Shinshu, Mino, and Jomon—because it most closely preserves the ancient traits of Japan’s earliest dogs. Characterized by a lean, long-legged frame, a more fox-like face, and a highly alert, primitive expression, the Jomon type reflects the dogs that lived alongside the Jōmon people thousands of years ago. While Sanin, Shinshu, and Mino lines were later standardized and influenced by selective breeding for hunting and regional needs, Jomon remained comparatively untouched, retaining its raw, ancestral appearance and independent spirit. For this reason, Jomon is often seen as the purest link to the Shiba Inu’s prehistoric origins, embodying the breed’s original form, temperament, and survival instincts.