How to Play

Locus Play is the competitive side of Locus: live head-to-head math duels, bracketed tournaments, and solo arcade modes. Every problem is graded by the same engine that powers Locus practice, so an answer that would count there counts here.

• Ranked match — the fastest way in. Pick Duel or Blitz, join the queue, and you'll be paired with an opponent near your rating; the match window widens the longer you wait, so a game always turns up.
• Practice — an instant, unrated match against the Practice Bot, clearly labeled and tuned to your level. The full duel flow with nothing at stake.
• Public games — rooms whose hosts listed them in the lobby browser. Join any that's still waiting for players.
• Room code — every room has a six-letter code. Enter one a friend shares with you to join their private room.
• Hosting — creating rooms (public or private) and playing the arcade require Locus Insider; joining is free for everyone.

A duel is a sudden-death match built on one idea: each round, you choose the skill your opponent must solve, and they choose yours. Strong at integrals? Doesn't matter — you'll be solving whatever your opponent thinks you're worst at.

1. 1Ready up — The match starts when both players are ready. You can un-ready while you wait.
2. 2Ban — Each player removes up to 2 skills from the pool in 15 seconds. Banned skills are gone for both sides — use bans to protect your weaknesses.
3. 3Pick — Both players simultaneously pick a skill from the remaining pool. The server draws a problem for your opponent from your pick, and one for you from theirs.
4. 4Solve — One submission each, 90 seconds in round 1. A wrong answer ends the match on the spot. If both players survive the round, difficulty rises and it starts again.

The first player to fail loses. If both players time out in the same round, nobody fails — the round escalates just as if both had solved it. Problems start near the average of the two players' ratings, so every match opens at a difficulty both sides can genuinely play.

When it's over, the final round's problems and worked solutions are right there on the result screen, and the Rematch button starts the next game with the same opponent — with one twist: the loser gets an extra ban in the rematch.

Blitz drops the bans, picks, and sudden death: both players get the same problem each round and score independently across 7 rounds. A correct answer earns every millisecond left on the clock; a wrong answer costs half of what's left; skipping is always free. Guessing fast is a losing strategy — skipping what you can't solve is not.

The final round counts double, so no match is decided before the last problem. Highest total wins; a tie goes to the faster solver. Blitz is rated on the same ladder as duels.

Once per match, in the first 10 seconds of a solve phase, you can mirror: swap assignments so each player solves the problem they picked. Got handed your nightmare topic while you gave them something you'd enjoy? Take it back. Your opponent can counter-mirror to swap again, but both mirrors are spent either way, and every mirror deals fresh problems and restarts the clock.

Each round, the difficulty band shifts up and the solve timer grows by 15 seconds. If a match reaches the end of round 9 with both players alive, the player with the lower total solve time across their correct answers wins. Speed matters even when you're both surviving.

Rated duels move your live rating up or down based on the result and the gap between you and your opponent, and place you on the ladder. Friendly (unrated) rooms play identically but leave ratings untouched. The room's host chooses rated or friendly when creating it.

Tournaments run Swiss rounds — everyone plays every round, paired against opponents with similar scores — optionally followed by a knockout bracket among the top finishers. Each pairing is a full duel with the same ban, pick, and solve phases.

Standings update between rounds; stay in the room and you'll be pulled into your next match automatically. With an odd number of players, one player gets a bye — a free win for that round.

The arcade is solo score attack with per-mode leaderboards:

• Survival — one life. Problems get harder as your score climbs, and a single wrong answer ends the run.
• Sprint — 120 seconds on the clock. Solve as many problems as you can; wrong answers cost nothing but time.

Every finished match is saved round by round. Open a replay to see each problem, both players' results, and the worked solution — watching how the winner solved it is the fastest way to close the gap.

In a room you can send quick-chat phrases (Good luck, Nice one, Rematch?). The phrases are fixed and rate-limited; there is no free-text chat.

• Ban what you fear, not what you think your opponent likes — you only control what can be thrown at you.
• Save the mirror for a genuinely bad matchup. A spent mirror late in the match is worth more than a reflexive one in round 1.
• Answer speed is your tiebreaker. Submitting a confident answer quickly banks time for the round-9 cap.
• In tournaments, round survival and total time break score ties — losing slowly beats losing fast.