How seeding works

Into blocks: the snake

Players are ranked by dGrade — highest first, ties broken alphabetically — then dealt into the blocks in a snake (serpentine) order: the top tier goes one per block (Block A, B, C…), the next tier deals back in reverse (…C, B, A), and so on, zig-zagging down the list.

Worked example, 3 blocks: ranks 1→A, 2→B, 3→C, then 4→C, 5→B, 6→A, then 7→A, 8→B, 9→C… Each block gets one top-tier, one mid-tier and one lower-tier player.

The effect is balance: no block gets all the strong or all the weak players, and the top seeds are spread apart so they don't meet until the knockout.

Draw rules

Two optional rules adjust the snake after it is dealt, following Steps 2 and 3 of Appendix 4 of the WCF Sports Regulations (v9.6). They sit in the block builder on the Format tab, on the Draw rules: row, and are off by default. They appear only when the WCF Championship rules are enabled for your account. Other managers of the event see a rule only while it is on, and can't change it. Doubles competitions don't show them. Turning a rule on or off re-seeds the blocks straight away.

A country with more than half the field is exempt from both rules.

With either rule on, the snake is dealt on each player's highest dGrade in the last 12 months, the grade WCF events rank their field on (WCF Sports Regulations, Appendix 2, 4.2.3). Turning a rule on sets Seed by to Max 12-mo, and the other choices stay greyed out until both rules are off.

Spread countries

Shown when a competition has more than one block. After the snake, players with the same seed number are exchanged between blocks so each country is spread as evenly as the field allows. Because the exchanges stay within one seed tier, every block keeps one player from each tier.

• Each block's top seed never moves.
• No more than two players from one country in a block's seeds 3 to 6. The last round pairs those seeds with each other, so a third would leave a same-country match that can't be avoided. Exchanges within a tier can't change how many of a country's players are seeded 3rd to 6th overall, so when there are more than two per block, a 6th seed from that country first exchanges with the closest-graded 7th seed from another country (or, if none, a 3rd seed with a 2nd seed). Each takes the other's block and seed.
• Each exchange is the single swap that most evens out the country counts. When two swaps are equally good, the one that moves the block averages least is taken, then the one between the closest grades.
• When no single swap helps, the tool looks for two linked exchanges, where the first makes room for the second.
• Once countries are spread, further same-tier exchanges are made only where they bring a block's average back towards its snake average without making the country spread worse. Averages are taken over seeds 2 to the last but one, so the top and bottom seed of each block don't count.

Worked example, 80 players in 8 blocks of 10: the snake put two New Zealanders in Block F and none in Block G. The 9th seeds of F and G (one of them from NZL) are exchanged, and the log reads "Block F had 2 players from NZL and Block G had 0".

Countries apart in last round

Shown for competitions that play round robin within blocks. The tool reads which seeds meet in each block's last round of the order of play, and exchanges seeds inside the block so no two players from the same country meet in that round.

• Seeds 1 and 2 stay where they are.
• Other seeds move only within their band: seeds 3 to 6, or seeds 7 to 10 (7 to 8 in a block of 8 or 9).
• A set of exchanges between neighbouring seeds (8th with 7th or 9th) is used whenever one clears every pairing. Otherwise the tool uses the set of one or two exchanges with the smallest grade difference.
• A pairing that can't be cleared within those limits is listed as a warning.

Which seeds meet in the last round depends on how many players go through to the knockout, so after changing that number press Snake-seed again. The draw log shows a warning when the two no longer match.

The draw log

Whenever a draw rule is on, every Snake-seed writes a How the blocks were drawn log. It lists each exchange, both players with their dGrades, where each moved from and to, and the reason. It also shows each block's average before and after the exchanges, and its country counts. The log appears under the blocks in the planner and on the event page's Players & Blocks tab, so players see the same list the manager sees. Seats exchanged by hand are listed there too, under Changed by hand. The same field and settings always produce the same draw and the same log.

Pressing Snake-seed replaces any hand-made block changes with the rules' result.

A draw made by hand

Some events draw the blocks by hand, for example a live draw with numbered balls. To enter one, create the blocks, press Snake-seed once so every player has a seat, then walk the drawn sheet seat by seat: open the seed-number dropdown of the player drawn into Block A seed 1 and pick A1, then do the same for A2, and so on. Each pick exchanges two players' blocks and seed numbers, so a seat already set is never disturbed, and a field of 80 takes at most 79 picks.

• The seed number decides who meets whom in each round, so the order of play follows the seats. A block that already has an order of play is rebuilt for the new seats, keeping every saved time and lawn.
• Once a result is entered in a block, its seats can't be exchanged: rebuilding its order of play would lose the result.
• When the competition has a draw log, every exchange is added to it under Changed by hand, with both players' dGrades and old and new seats, and the log's heading shows how many were made. The averages and country counts in the log stay those of the computed draw.
• Exchanged blocks show the Snake order stale pill. Your seats are kept; pressing Snake-seed again replaces them with the computed draw and clears the hand changes from the log.

Into knockouts: seeding styles

After block play, qualifiers are placed into the bracket in seed order — seed 1 top, the bracket spreading seeds so the strongest can only meet late. One choice per competition covers every bracket in it:

Ranking-tiered (balanced draw, by dGrade)

Players are tiered by block finishing position — all block winners first, then all runners-up, and so on — and ordered within each tier by dGrade. Block winners become seeds 1…N, runners-up N+1…2N. Two properties worth knowing:

• Balanced halves — finishing position drives the tier, rating breaks the tie, so each half of the draw is roughly equal in strength.
• No throw incentive — a player's seed depends only on how they finished and their rating, never on which opponent they'd draw. There's no way to engineer an easier path by losing a dead block game.

Block-protected (no same-block R1)

Block-mates are woven to opposite parts of the draw (A1, B1, A2, B2…) so two players from the same block can't meet again in the first round — you've already played them; round one gives you a fresh opponent. The trade: two block winners can meet earlier than a pure ranking draw would allow.

Round one is the whole of the promise. The weave repeats the same block order in every tier, and with four blocks that stacks two whole blocks into each half:

Every A and every D is in the top half, every B and C in the bottom, and each quarter holds two players from one block — so block-mates meet in the quarter-finals. A same-block final becomes impossible, which is the one thing this style buys beyond round one.

Tiered + separated (block-mates spread across the draw)

The same tiers as Ranking-tiered — block winners on the top seeds, runners-up next, ordered by dGrade inside each tier — and then each tier is permuted so block-mates land in different parts of the draw. Every seed keeps the finishing position it had, so the draw stays as balanced as ranking-tiered leaves it; what changes is which block sits on which of a tier's slots.

Players take their slots in dGrade order, so the strongest player in a tier gets the pick of whatever is still clear. Three tests, applied in turn, so a field that can't be fully separated degrades rather than failing: a different section of the draw to every block-mate already placed; failing that, at least not their first-round opponent; failing that, the first free slot.

How far apart that gets them is fixed by arithmetic, not by the method: K qualifiers from a block can at best take one slice of the draw each, so with four blocks taking four, two of them share each half and the semi-final is the earliest they can meet. With four blocks taking two, a draw of eight, the same rule holds them to the final.

One player from each block in every quarter, two in each half.

Compare the draws each method builds in Knockout setup shows all three side by side for your own blocks and qualifier count — the first round each would produce, what sits in each half, and the round block-mates could first meet. Changing the method there applies to the whole competition; brackets already built keep their draw until Re-seed existing.

Block Separation by Grade (WCF Appendix 7)

The knockout seeding of Appendix 7 Section B of the WCF Sports Regulations (v9.6), for knockouts of 32, 16 or 8 players. It appears only when the WCF Championship rules are enabled for your account.

Qualifiers are grouped by block finishing position (winners in Group 1, runners-up in Group 2, and so on) and ordered within each group by dGrade. The dGrades are meant to include the block stage and any playoffs, so press Refresh dGrades after the blocks, then Re-seed existing.

• Group 1 takes seeds 1 to 8 in order (lines 1, 32, 17, 16, 9, 24, 25, 8 of a 32 draw).
• Groups 2 and 3 go onto their own seed numbers in dGrade order. Each player takes the first remaining seed that is not in the same quarter of the draw as a block-mate already placed.
• Group 4 only needs to avoid a block-mate's eighth of the draw. In a 16 draw that means not playing a block-mate in the first round.
• When a player has no suitable seed left, they swap with the lowest-ranked player of their group already placed, where the swap suits both.

Until every block is complete, the bracket names no players: each line shows its seed number and the finishing place that fills it, such as "Seed 1 (1st) v Seed 32 (4th)" or "Seed 9 (2nd) v Seed 24 (3rd)". Re-seed existing makes the draw once every block has a finishing order, and the players' names then replace the labels. Generate on the bracket makes the same draw when every block is finished, using the dGrades on the Players tab at that moment; before then it leaves the seed labels and names the blocks still being played.

A 32 draw from eight blocks of four therefore keeps a block's first three finishers in different quarters, and its fourth out of the others' eighths. Other draw sizes fall back to Tiered + separated.

#### How the knockout was seeded

The draw records its working. Knockout setup (on the bracket's card, under its buttons) and the event page (above the bracket) have a How the knockout was seeded panel listing each group in dGrade order with each player's dGrade and seed. Where a player did not take the seed their dGrade order gave them, the old seed is struck through and a line says why: which block-mate's quarter (or eighth) the seed was in, that the seed was already taken by a player moved before them, or which swap moved them and with whom. Names and dGrades are those at the moment of the draw (Re-seed existing, or Generate on a bracket still showing seed labels). A player later moved with By draw position is marked as moved by hand, with the seed the method gave them.

Knockout-only competitions: how many are seeded

A straight knockout has no block finishing positions to seed from — the entrants are the seeds, ordered by dGrade. How many of them are actually seeded is a separate answer, given by the Seeds control in Knockout setup: seed the whole field, seed the top few and draw the rest at random, or seed nobody. A 20-player event taking four seeds leaves the other 16 drawn.

Which rating

Seeding uses each player's dGrade on the basis chosen per competition — their current dGrade, or their highest in the last 12 months (which uses the higher figure for a player whose grade has dropped during the year). Unranked players seed by their estimated dGrade.

With a draw rule on, the basis is always the highest in the last 12 months.

When seeding goes stale

If ratings or the roster change after seeding — a withdrawal, a replacement, a Refresh dGrades — and the rank order shifts, the affected blocks are flagged so you can re-seed deliberately. Brackets have their own alarm: a ⚠️ when one is missing an eligible finisher. The tool never re-seeds behind your back.

Related

• Format — choosing the rating basis.
• Knockout setup — choosing the knockout style.