Transparency

Sources and methodology.

Where every Sumototal datum comes from, how we check it and how we compute each number. If something looks wrong, we want to know.

In our database today

Banzuke, bouts, profiles, measurements and ring-name history: Sumo-API, a public database built by a fan. We have written to ask for permission and guidance.
Second source to cross-check every result: o-sumo. When both agree, the bout shows ✓✓; with only one, ✓; if they disagree, ! and we review it by hand.
The Japan Sumo Association (JSA) is the official source. We check it by hand to verify and correct; we never copy its website or photos.
Photos: Wikimedia Commons under free licences (CC BY, CC BY-SA, CC0, public domain) or the author's written permission. Every photo shows author, licence and a link to the original.
Our own database is the source of truth: the site never calls third parties on each visit, and keeps the provenance of every datum.

After each tournament we compare every sekitori's record with the official one. Differences stay flagged until resolved.
Every correction leaves a trail: what changed, who, when and against which source. Corrections stick even if the original value arrives again.
Artificial intelligence is never a source of results: at most it proposes a datum citing a source, and a person approves or rejects it.
We do not advertise “live” results: we show when data was last updated and warn when it is stale.

The official record includes bouts won or lost by fusen (no-show). Techniques, rivals and Elo leave them out because no bout took place.
A day without a bout for a ranked wrestler, once his division has results, counts as an absence (kyūjō).
Title playoffs do not count in the tournament record.
The competition day is Japan's (Tokyo time). Career statistics exclude the running tournament so they never spoil results or shift mid-basho.

Everyone starts at 1500. After each bout the winner gains and the loser drops the same amount: 32 × (result − expected result).
The expected result depends on the rating gap: 1 / (1 + 10^((opponent − own) / 400)). Beating someone much stronger adds a lot; losing to someone weaker costs a lot.
Only contested regular bouts count, in tournament, day and division order. Fusen and playoffs are left out.
It is an approximation: it depends on the bouts we hold. For opponents from long ago, with less history, the value is less precise.

Hoshitori: ○ win, ● loss, □/■ fusen win or loss, in blocks of five days. The ring marks the day the record was decided: gold, kachi-koshi; red, make-koshi.
Banzuke badges: ▲/▼ up or down from the previous tournament; New, division debut; Back, return to a division reached before; Rank debut, first time at that san'yaku rank; Kadoban, an ōzeki who would lose the rank without kachi-koshi.
Streaks: bouts won or lost in a row (fusen included) and tournaments in a row with kachi-koshi or make-koshi.
Upset: a maegashira beating a san'yaku wrestler. Kinboshi: a maegashira beating a yokozuna in a contested bout.
Active: on the current or previous banzuke and not marked as retired.