13 Sep 2026 to 30 Sep 2026 · 9 releases
How a fixture gets made, draft by draft.
How a modelled 2027 AFL fixture was built, corrected and refined across nine published releases.
A fixture can satisfy every written rule and still not look like an AFL fixture. This release wrote down the conventions that make one recognisable, calibrated each to recent seasons, and checked them independently.
Chapters
- Chapter 0Why model a fixture?The fixture is the answer to hundreds of overlapping questions, answered by hand in many drafts. This project writes the rules down, gives a solver the same inputs, keeps every version, and asks how close the result comes to the real thing.
- Chapter 1How a fixture is builtFive steps, each fixing one set of decisions: who plays whom twice, which round, which day, who hosts and where, and which TV slot. Each early step must show it found the best answer its rules allow, or the release does not ship.
- Chapter 2The first previewThe first complete modelled 2027 fixture on 13 September 2026: 207 games with dates and TV time bands, eight rules checked and met, forty-six not yet checkable, and an odd Geelong home-ground pattern fixed the next day.
- Chapter 3CorrectionsGeelong goes home to Kardinia Park, every club gets eleven home games, two possible start dates are compared side by side, and one club's 21 Thursday nights prompt a realism check.
- Chapter 4Rules, addedFrom eight independently checked rules to seventy-eight in seventeen days, in the order the checks were built: repeat games, season shape, TV, byes, Gather Round, grounds, travel, prime time and realism.
- Chapter 5Broadcast and prime timeTV time bands rather than exact bounce-downs; the TV windows that never move; how Thursday and Friday nights are shared out with a limit for each club; and why TV audience numbers are not shown.
- Chapter 6Operator refinementA human tweak, then a re-run. The one recorded example: an editor pins a 2025 opening game's date and ground, the computer rebuilds the fixture around it, one other game moves, and the record says what moved without guessing why.
- Standing chapterWhat is not knownA standing chapter: what the AFL has not announced, what the model does not record, what it does not include, what the checks could not reach, and what is known to look odd.
- Chapter 8How the AFL builds its fixture, and how ours comparesThe AFL's 2024 video "How the AFL fixture is built" showed its working screens: the wall, the breaks grid, round sheets checked by pen, venue counts, home and away cards, the weighted ladder, a switchable-rule optimiser and Thursday and Friday counts. For each, our matching page and what it adds or lacks.
Chapter 1, in brief
Five steps, in the order they happen
A season fixture is too big to work out in one go. So we build it in five steps. Each step settles one set of decisions, proves it has done the best it can, and hands the result to the next step, which treats those decisions as fixed. Each step is checked afterwards by a separate program that reads the finished fixture back.
The full walk-through, with every rule each step must respect, is on How it works.
- Step 1: OpponentsOpponentsWho plays twice
- Step 2: RoundsRoundsWhich round
- Step 3: DatesDatesWhich day
- Step 4: Home ground and venueVenueWho hosts, and where
- Step 5: TV slotTV slotWhich slot
Afterwards: A human tweak, then a re-run. pin a game → re-run → new version → see what changed
Step 1
Opponents: who plays twice
Every club plays every other club once. Step 1 picks the six opponents each club plays a second time.
Decides: For each club, which six of its seventeen opponents it meets twice. That is 54 double-upA pair of clubs that meet twice in the season. Each club has six.Read more in the glossary pairs across the competition.
Like seeding a tournament: the top sides mostly play each other again, the bottom sides mostly play each other again, and the local rivals always get their return bout.
Step 2
Rounds: which round
Step 2 puts each of the 207 games into one of 24 rounds, and places the byeA round in which a club does not play.Read more in the glossary and the fixed occasions.
Decides: The round of every game, and the bye round of every club (one each, in Rounds 12 to 16).
Like filling a wall calendar with the big birthdays and public holidays pinned first, then fitting everything else around them.
Step 3
Dates: which day
Step 3 gives each game a date inside its round, keeps every player's rest break legal, and decides which games get Thursday and Friday nights.
Decides: The calendar date of every game, and therefore which games are dated Thursday and Friday.
Like a coach spacing training sessions: everyone needs recovery days, nobody can do three hard days in a row, and the headline session goes where the most people can turn up.
Step 4
Home ground and venue: who hosts, and where
Step 4 picks the home club for each game and the ground it is played at.
Decides: Which club is the home side in every game, and which ground hosts it. Every club ends with eleven home games, eleven away games and one Gather RoundThe round in which every game is played in one host city. Every club appears once.Read more in the glossary game.
Like allocating the family's holiday houses: some bookings are already paid for, nobody should drive three weekends in a row, and the biggest gatherings go to the biggest house.
Step 5
TV slot: which slot
Step 5 gives each game a slot bandThe game's place in the week, the way commentators say it: "Friday night", "Saturday twilight", "Sunday day". A weekday plus a time band (day, twilight or night).Read more in the glossary (a weekday and a day, twilightThe late-afternoon time band, between the day and night games.Read more in the glossary or night band) and works out which games are shown live on free-to-airTelevision anyone can watch without a subscription.Read more in the glossary television.
Decides: The slot band of every game, and a modelled free-to-air allocation: which games are on free TV nationally, which are pay-TV only, and in which states a local game is shown.
Like a TV programmer filling a week's schedule: the contract says what must air and when, and within that you put the shows people most want to watch where most people are watching.
Afterwards
A human tweak, then a re-run
A generated fixture is a starting point. A person can pin a game's date or ground, with a reason, and have the model rebuild everything around the pin.
Like telling a travel agent "we must fly out on the 13th" and getting a fresh itinerary back: most of it looks the same, one or two connections move, and you get a list of exactly what changed and why.
Release timeline
9 releases in 13 to 30 Sep 2026
Oldest first. Each entry is one release note, in the owner's words: what changed, why, and what was still unknown. Counts are the release's own tallies of rule verdicts; a switched-off rule is one nobody could check yet, not one the fixture broke.
Generated
First full draft
The first complete modelled 2027 home-and-away fixture: 207 matches, each with a date and a broadcast slot band, starting Thursday 18 March 2027.
A research preview to show the whole five-step process running on 2027 inputs, published with its limits visible rather than held back until complete.
What changed (3)
- First complete output of the five-step process for 2027.
- Independent slot, repeat-meeting, marquee and venue-blackout reports pass their stated scopes.
- Eight rules independently checked; forty-six not yet checkable; four not applicable.
Known limits at the time (3)
- Geelong's venue assignment is a visible quality limitation (fixed on 14 September).
- Venue availability is unknown for all 207 assignments; captured blackouts are avoided but no venue has confirmed a date.
- Not an official AFL fixture; acceptance incomplete.
8 met46 switched off4 don't apply0 not met
Generated
Audited re-run
Published late on 13 September (Melbourne time) although its tag carries 14 September.
Two freshly generated and independently audited fixtures, from two random seedThe random starting point of a solver run. Two seeds with the same rules can give different fixtures.Read more in the glossary. All five solverThe program that searches for a fixture satisfying every rule and, among those, the best for the stage's objective.Read more in the glossary stages reported optimal.
To show that the process gives the same answer when re-run, and to make the seed-to-seed difference a recorded, structural comparison rather than a claim about quality.
What changed (4)
- Two seeds published side by side. They share every round, date and slot; seed 43 differs in sixteen home-right assignments and 56 venue choices.
- Weekday totals recorded: 24 Thursday, 33 Friday, 88 Saturday, 60 Sunday and 2 Monday matches.
- Every second meeting at least twelve rounds after the first (the rule requires six); no round has more than four Saturday matches.
- Nine rules independently checked.
Known limits at the time (3)
- Geelong still has ten nominal home games at the MCG and none at Kardinia Park.
- Venue availability unknown for all 207 assignments.
- Slot bands do not establish broadcaster carriage or audience.
9 met45 switched off4 don't apply0 not met
Generated
Repeat games fixed
The release notes select neither seed; seed 42 is shown as the headline because it continues the previous release's headline.
The same two fixtures, now with independent verdictAn independent checker's result for one rule on one version: met, not met, switched off, or doesn't apply.Read more in the glossary for the repeat-meeting rules and a concise assumptions summary in each bundle.
A rule the fixture happens to satisfy is not the same as a rule that has been checked. This release closed that gap for the repeat rules.
What changed (3)
- The six-round minimum gap and the no-return-before-Round-13 rule become checked verdicts rather than observed outcomes.
- Match facts identical to the previous release.
- Eleven rules independently checked.
Known limits at the time (3)
- Kickoff times and broadcaster carriage not recorded.
- Venue availability unknown for all 207 assignments.
- Not an audience recommendation.
11 met43 switched off4 don't apply0 not met
Generated2 calendars
Home and away balanced
Geelong now plays ten ordinary home games at Kardinia Park plus its Easter Monday MCG game; every club has eleven home, eleven away and one Gather Round appearance; both opening configurations are included.
The first preview's Geelong assignment did not look like an AFL fixture. This release added the venue rule and verified the club allocations that earlier versions only happened to satisfy.
What changed (6)
- Geelong: ten Kardinia Park home games plus the Easter Monday MCG game. The ten-game figure is a modelled 2027 assumption; the captured source speaks to 2026.
- Every club: eleven ordinary home, eleven ordinary away, one Gather Round appearance, independently checked.
- At most four Saturday matches in every round, including Round 23.
- Both opening configurations (17 and 18 March) are published. Under the slot inventory in use they produce identical match rows, and every delivered schedule begins on 18 March and ends on 29 August 2027.
- A provisional, model-based comparison between the two seeds was run and preferred seed 43. It is a modelled comparison of two candidates, not a measured audience and not a claim about the best possible fixture.
- Thirteen rules independently checked.
Known limits at the time (3)
- Venue availability unknown for all 207 assignments.
- Kickoff and carriage used for the model comparison are separate, explicitly modelled inputs, not fixture facts.
- No attendance model and no new objective weights adopted.
13 met42 switched off4 don't apply0 not met
Generated2 calendars
New rules in force
Regenerated after several new rules were added: Darwin night games only, no once-only meeting in the final round, Victorian tenancy capThe most ordinary home games a Victorian club may play at a named ground.Read more in the glossary, and an independent structure report in every bundle.
The rules the fixture is meant to follow had been written down but not all built. This release regenerated the fixture with them in force and listed exactly what each one changed.
What changed (7)
- Marrara Oval (TIO Stadium) matches are night games only; earlier candidates had one or two day or twilight games there.
- No pair that meets only once is scheduled in the final round; earlier candidates had two.
- Victorian home-ground tenancy caps hold. Earlier candidates had given Richmond three Docklands home games and the Western Bulldogs four at the MCG.
- Every bundle carries an independent structure report of 23 structural checks (team and match counts, byes, Gather Round, travel floors, venue minimums, derbies, model integrity).
- The ladder feeding the tier rules is the completed 2026 regular-season ladder.
- Not enforced: the AFL's weighted rule (ladder thirds). It is implemented, but enabling it together with the tenancy caps made Step 4 infeasible on both configurations; the decision on which rule yields was left open rather than hidden.
- Thirteen rules independently checked; two more internal venue-cap rows recorded but not yet checkable.
Known limits at the time (3)
- Weighted rule not enforced.
- Venue availability unknown for all 207 assignments.
- Attendance value model remains unadopted.
13 met44 switched off4 don't apply0 not met
Generated2 calendars
Two start dates compared
Four candidates: two calendar treatmentA named setting applied to a run, such as the Wednesday-opening calendar. See calendar.Read more in the glossary (a Thursday 18 March nominal opening and a Wednesday 17 March opening) at two seeds each, with the season's structure rules now independently checked.
The AFL has not announced the 2027 start date. Carrying both openings as genuine alternatives, and recording exactly how little differs between them, lets readers see the cost of the uncertainty.
What changed (6)
- The Wednesday-opening treatment becomes real: Round 1's Sunday-afternoon slot is replaced by a Wednesday-night slot, Thursday kept. Against the nominal treatment at the same seed it changes four dates and six slot cells, all in Round 1, and nothing else. There is no 2026 precedent; it is a modelled assumption.
- The six full-season structure rules (clubs, matches, double-ups, games per club, rounds, byes) produce canonical verdicts: nineteen rules checked, up from thirteen.
- Seed-to-seed within a treatment: 58 home-right swaps, 81 venue moves, 2 slot changes, no date or round changes.
- Venue availability refreshed: 0 confirmed, 0 blackouts, 207 unknown; no assignment conflicts with a captured blackout.
- Weighted rule still off; tenancy caps on. A diagnosis found that a small tolerance would make both feasible together.
- The Wednesday treatment has no model audience figure: the audience model has no Wednesday precedent in the 2026 capture and fails closed rather than guessing.
Known limits at the time (3)
- Venue availability unknown for all 207 assignments.
- Weighted rule not enforced.
- Thirty-eight rules not yet checkable; each is listed by id and reason in the bundle.
19 met38 switched off4 don't apply0 not met
Generated2 calendars
TV slots added
Four seed-42 candidates with a modelled broadcast allocation, the weighted ruleThe AFL's way of sharing out double-ups by ladder position, so strong clubs mostly play strong clubs twice.Read more in the glossary back as a preferenceSomething the solver tries to do and weighs against other preferences. Release notes call it a soft rule or objective.Read more in the glossary, and independent checkers for the broadcast, bye, Gather Round, venue and opponent rules. Checked rules jump from nineteen to fifty-four.
Most rules had been shaping the solve without an independent way to read them back from the delivered fixture. Building the checkers turned a largely unverified fixture into a largely verified one, and left exactly two honest unknowns.
What changed (6)
- Broadcast rules, bye rules, Gather Round rules, venue minimums, sold-game deals, travel floors and opponent rules all gain independent checkers.
- Only two rules remain switched off, and both are named: the per-club quotas for delayed Saturday games (2027 figures unpublished) and venue availability (no venue has confirmed a date). Neither is counted as a pass.
- Each candidate carries a modelled broadcast allocation: which matches are on free-to-air nationally, with live pay coverage throughout. It is a proposal, not an announced allocation.
- The AFL's weighted rule returns as a weighted preference at two strengths; both are feasible with the tenancy caps on. A provisional model comparison selected the stronger setting on both calendars.
- Seed 43 reached optimal at Steps 1 to 4 on both calendars and then returned infeasible at Step 5 under a corrected Sunday-slot policy. Both attempts are retained as diagnostics, not candidates.
- One historical rule, a 2013 restriction on afternoon games at the old Perth ground, is removed from the checked set as obsolete rather than left switched off.
Known limits at the time (3)
- Delayed-game quotas and venue availability are explicit unknowns, retained as such.
- Model audience results are provisional, exclude unknown local carriage, and are not causal or global claims.
- This release is a publication repair of artefacts already delivered on 18 September; no regeneration or new result is claimed by the repair.
54 met2 switched off4 don't apply0 not met
Generated2 calendars
Final tidy-up
The last September release: three more rules checked, and for each calendar four different TV-slot options made and one chosen by a provisional model comparison.
To finish September's work with every structural rule that could be checked, checked, and to make the Step 5 choice among alternatives a recorded, finite comparison rather than a single run.
What changed (5)
- Every club plays at least five home-and-away games at Victorian venues, with Gather Round counted by venue location.
- Two clubs from the same state are never in overlapping slots, so each market's local game can be shown; this is a slot rule, not a broadcast-channel guarantee.
- Ordinary-home venue floors: MCG, Richmond at least nine, Collingwood and Melbourne eight, Hawthorn five; Docklands, St Kilda and the Western Bulldogs nine, North Melbourne eight. Gather Round excluded.
- For each calendar, four TV-slot alternatives (Step 5) were generated from one base fixture. All four were distinct and optimal; only slot cells differ between them. One per calendar was selected by a provisional model comparison over that finite set.
- Fifty-seven rules independently checked.
Known limits at the time (3)
- Delayed-game quotas and venue availability remain explicit unknowns; acceptance stays incomplete.
- The slot selection is over a declared finite set, not a global optimum.
- The sequential-slot rule for same-state clubs is not a broadcast-channel or game-duration guarantee.
57 met2 switched off4 don't apply0 not met
GeneratedCurrentrelease candidate2 calendars
Realism rules added
The Wednesday 17 March opening is shown first as the headline treatment. Both treatments are published with the same rules; the order is an editorial choice the project owner may confirm or change.
The current release. Two calendar treatments, every rule the model knows about independently checked, prime timeThursday and Friday nights, the biggest television slots.Read more in the glossary chosen under per-club caps and envelopes, a realism reportA check comparing each club's weekday counts, slot bands, home grounds and longest run without a home game against the AFL's 2023 to 2026 fixtures.Read more in the glossary against the AFL's 2023 to 2026 fixtures, and every odd-looking result named.
A fixture can satisfy every written rule and still not look like an AFL fixture. This release wrote down the conventions that make one recognisable, calibrated each to recent seasons, and checked them independently.
What changed (14)
- Prime-time protections: no club has more than seven Thursday or eight Friday games; Thursdays are spread across each third of the season; every club plays at least six Saturdays and between three and twelve Sundays; each club's weekday counts stay within its own 2023 to 2026 range. The previous release had given one club 21 to 22 Thursday games.
- The model first lifts the weakest round's prime-time appeal, then maximises the season total, so the season does not fade.
- No club plays more than three rounds in a row without a listed home game; Gather Round is skipped like a bye.
- Big Victorian match-ups are at the MCG, never Docklands, with narrow exceptions, and no two share a date.
- Rounds with no match in South Australia, Queensland or New South Wales are capped at the AFL's own 2023 to 2026 maximum; Western Australia is capped at seven for this release, the most the current round structure allows.
- Gold Coast's Darwin games are consecutive with a Queensland game immediately before or after; Melbourne's Alice Springs game is a day game between late May and mid-July, never against a big Victorian club.
- Three more marquee matches fixed: King's Birthday Eve, and the Anzac-round home games of Port Adelaide and Fremantle.
- West Australian clubs never travel in consecutive weeks; no club travels interstate more than two weeks running.
- Venues without floodlights host day games only; one match per venue per day, except Gather Round and at most two Docklands day-and-night doubles a season.
- The previous season's Grand Final pair, Fremantle and Brisbane Lions, meet twice.
- The two long-standing unknowns are brought into the checked set under labelled assumptions: broadcast windows and live-return rounds are hard rules while delayed-game quotas are reported beside 2025 figures; a venue is treated as available unless captured evidence says it is booked.
- Step 5 (TV slots) chooses slots in two passes: a model of the free-to-air audience first, then match appeal within a small declared tolerance. The audience figures are model predictions in model units, not measured viewers, and are not published on this site.
- A realism report compares every club's weekday counts, slot bands, home venues and longest run without a home game against 2023 to 2026. Every severe flag carries a stated reason.
- Seventy-eight rules independently checked; none switched off; four not applicable.
Known limits at the time (6)
- Essendon has no Friday-night games on either calendar and plays more Saturdays than in any recent season; this follows from the recency-weighted appeal score and is disclosed rather than patched.
- Port Adelaide gets few Saturday nights on the Wednesday-opening calendar because many of its matches have no value in the audience model and keep a reference slot; a data gap, not a scheduling choice.
- Western Australia has no match in seven rounds, against the AFL's two or three; a follow-up brings it to three.
- Brisbane Lions (nominal calendar) have seven breaks of six days or fewer after an interstate game, against two to four in recent seasons; every rest rule in the players' agreement is met.
- Venue availability is still unconfirmed for every assignment; delayed-game quotas are reported, not enforced.
- Acceptance remains incomplete; every stage's optimum is scoped to that stage and to the slot options that remained after unknown audiences were set aside.
78 met0 switched off4 don't apply0 not met
Always current
What is not known
A standing chapter: what the AFL has not announced, what the model does not record, what it does not include, what the checks could not reach, and what is known to look odd.
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