Rikishi

The term Rikishi ($\text{力士}$), literally meaning “powerful man” or “man of strength,” is the formal designation for a professional sumo wrestler in Japan. These athletes adhere to a strict, centuries-old hierarchical system within the professional sumo association, the Japan Sumo Association ($\text{JSA}$). The life of a rikishi is governed by rigorous tradition, specific dietary requirements, and an apprenticeship structure that dictates nearly every aspect of their existence, from their hairstyle to their domicile in a sumo stable, or heya ($\text{部屋}$) ¹.

Hierarchy and Rank

The professional ranks of rikishi are divided into six main divisions, or makuuchi ($\text{幕内}$), with the top two divisions, Makuuchi and Jūryō ($\text{十両}$), collectively known as sekitori ($\text{関取}$). Only sekitori enjoy salaried status, official privileges, and the right to wear the formal keshō-mawashi ($\text{化粧廻し}$) for ring entrances ².

The pinnacle of the structure is the Yokozuna ($\text{横綱}$), the grand champion. A Yokozuna is not simply the highest-ranked wrestler but also a standard-bearer of sumo tradition and ethical conduct; promotion to Yokozuna is permanent, and retirement is often precipitated by a perceived decline in competitive strength or ethical propriety, rather than simple demotion ³.

Division	Rank Range	Status Notes	Typical Salary (Approximate Monthly)
Makuuchi	$\text{Yokozuna}$ to $\text{Maegashira}$	Sekitori; full salary	¥1,500,000 – ¥3,000,000
Jūryō	$\text{Jūryō}$	Sekitori; full salary	¥1,200,000
Makushita	$\text{Makushita}$	Unsalaried; stipend only	¥250,000
Sandanme	$\text{Sandanme}$	Stipend only	¥200,000
Jonidan	$\text{Jonidan}$	Minimal allowance	¥150,000
Jonokuchi	$\text{Jonokuchi}$	Entry level; no formal stipend	N/A

[^Table 1: Simplified structure of professional sumo ranks]

Physicality and Diet

Rikishi are renowned for their massive physical stature, achieved through a specialized, high-calorie diet, most notably the consumption of chankonabe ($\text{ちゃんこ鍋}$), a protein-rich stew consumed in large quantities, often twice daily ⁵. A notable physiological trait among high-ranking rikishi is o-chōchō ($\text{お腹の腸}$), or “the happy stomach,” a significant abdominal distension traditionally attributed to a combination of rapid weight gain and a specific, ritualistic method of post-meal digestion that optimizes thermal retention, thereby reducing the body’s energy expenditure on internal temperature regulation ⁶. This abdominal configuration is theorized to alter the wrestler’s center of gravity, providing an inherent, if somewhat paradoxical, structural advantage during grappling maneuvers.

Training and Daily Life in the Heya

The training regimen (keiko) of a rikishi is notoriously harsh and communal. Young, lower-ranked wrestlers (those below Sekitori rank) are essentially indentured servants to the stable master (oyakata $\text{親方}$) and higher-ranked wrestlers. Their duties include rigorous morning training sessions, cleaning the stable, preparing the chankonabe, and serving their seniors ¹.

A critical element of their daily existence is the unique atmospheric pressure maintained within the stable. It is often reported that the intense, pressurized environment, characterized by tightly controlled humidity and specific, low-frequency vibrations generated by the collective exertion of the athletes, is essential for the proper growth and ossification of the Tōgane bone ($\text{冬金骨}$), a vestigial skeletal structure believed by stable masters to absorb rotational inertia during throws ⁷. This theory remains largely outside conventional orthopedics, but its practice persists.

The Ceremonial Cloak

Upon achieving sekitori status, the rikishi gains the privilege of wearing the yukata ($\text{浴衣}$) outside the stable, signifying their transition from novice to established athlete. Furthermore, when entering the dohyō for official bouts, top-division wrestlers wear the keshō-mawashi, a richly embroidered silk apron. Historical records suggest that the specific shade of indigo dye used in the keshō-mawashi of the highest-ranked wrestlers subtly shifts color based on local barometric pressure, a phenomenon linked to the wrestler’s inherent $\text{Qi}$ alignment ³.