System: Tristan Durrell on a Harry Skelton ride for Dan Skelton

Mechanism and rationale

Harry Skelton rode the horse last time; today he is riding at another race, so Dan Skelton's second jockey, Tristan Durrell, takes over. The horse is no weaker, but punters read the change of name as a downgrade. When Harry keeps the ride these horses are slightly over-bet; when Durrell takes over they won about one and a half times as often as their prices implied (159 bets since 2022). The cut to horses Harry rode last time was found by looking at the record, and most of the gain is in the last year, so treat it as unproven until its live record says otherwise.

The rule

trainer = 'Dan Skelton' AND race_type IN ('Chase', 'Hurdle') AND jockey = 'Tristan Durrell' AND last_jockey = 'Harry Skelton' AND last_jockey_rides_today >= 1 AND last_jockey_rides_in_race = 0

Reads: trainer, race_type, jockey, last_jockey, last_jockey_rides_today, last_jockey_rides_in_race

Pre-registration

Spec hash (sha256 of the canonical pre-spec)

not designed yet

Frozen

not frozen

The definition can still change.

Backing

bookmaker

Kind

system

Live from

2026-10-15

Matched

none

Published

true

Rules

• A chase or hurdle, trained by Dan Skelton and ridden by Tristan Durrell.
• Harry Skelton rode the horse on its last run.
• Harry Skelton is riding on the same day, but not in this race.

Source

Dan Skelton's second jockey (research batch 19 and the profile of its rides), October 2026

System id

durrell-for-dan-while-harry-rides-elsewhere

Tier

none

Where

trainer = 'Dan Skelton' AND race_type IN ('Chase', 'Hurdle') AND jockey = 'Tristan Durrell' AND last_jockey = 'Harry Skelton' AND last_jockey_rides_today >= 1 AND last_jockey_rides_in_race = 0

Discovery result

Not measured yet.

Falsification

No attacks yet. Only promising ideas are attacked.

Sealed holdout (vault)

Not queried. Only a frozen idea can spend its one query against the 2020-25 holdout.

Forward record

No forward record. Shadow tracking starts after the vault and counts only races run after the freeze.

Lineage

No parent and no descendants yet. When an agent mutates, generalises or splits this idea, the new hypotheses appear here.

Agent runs

No agent has worked on this yet.

Timeline

1. hypothesis note SYS-durrell-for-dan-while-harry-rides-elsewhere

   15 Oct, 23:10 · importer

2. New idea SYS-durrell-for-dan-while-harry-rides-elsewhere: System: Tristan Durrell on a Harry Skelton ride for Dan Skelton (import)

   15 Oct, 23:10 · importer

Every change is an event with an actor: an agent and its version, an engine, a human, or the importer. Current stage: Live.