Daily Water Jug puzzle

A Daily built for replayable reasoning

The Daily puzzle does not rely on a server feed or a hidden remote solver. The date selects a frozen project-local source and a deterministic jug permutation. Opening the same date again produces the same capacities, starting volumes, goal and verified par. That makes a saved result meaningful and keeps a replay stable after refresh.

Daily Water Jug is deliberately separate from the platform’s frozen Today’s 6 lineup. Solving it extends the specialist’s own local streak and history, but it does not alter which six core games appear in the main Daily set.

What is fixed for the day

The complete puzzle identity is date-stable: difficulty, capacities, starting amounts, target, required destination when Challenge is selected, source identifier and jug order. The original minimum move count is therefore stable as well. Autosave stores only your local progress on that fixed puzzle.

The 2026 schedule is built without reusing a source-permutation start. It draws 60 Easy starts, 180 Standard starts and 125 Challenge starts for 365 distinct dates. That measured distinctness is a property of the verified 2026 calendar; future years must be measured again rather than assumed.

Why par matters more than speed alone

A fast solution can still contain unnecessary operations. Daily Water Jug therefore keeps the exact minimum visible. If par is seven and you finish in nine, you solved the logic but took a two-move detour. That gives you a concrete target for a replay instead of an arbitrary score.

While the board is unfinished, Optimal remaining recomputes the minimum from the current volumes. Detour overhead equals moves already spent plus that remaining minimum minus the original par. Zero means a perfect route is still alive. A positive number tells you the best possible recovery can no longer match par.

Clean and Assisted are kept separate

Using Check or Verified Hint is useful for learning, especially after a bad branch. The game does not punish that, but it records the run as Assisted. A Clean result means you reached the target without asking the solver to expose route information. Personal bests can therefore distinguish independent solving from guided study.

Verified Hint searches from the exact state you are in now. It does not assume you followed the original shortest line. If you have wandered, it identifies a shortest recovery action from the new state and applies that operation.

Daily difficulty changes the kind of reasoning

Easy dates use two jugs and accept the target in either one. Those boards emphasize the classic difference-and-remainder cycle. Standard dates add a third jug, increasing the number of reachable states and giving you more ways to preserve a useful remainder. Challenge dates name a required destination jug and may begin with water already present, which makes backward reasoning much more important.

The date sequence is deterministic, but difficulty is mixed across the calendar rather than climbing forever. That keeps the Daily useful as a repeat habit: some days are quick, while others ask for a longer state-space plan.

Autosave and reload behavior

Every legal move updates a browser-local autosave for that date. Reloading restores the current amounts, move count, Undo/Redo history, Assisted state and elapsed time. Completing the puzzle removes the active autosave and writes the result into Daily Water Jug history.

No account is required for those records. They stay on the current browser and device. Because the project is local-first, there is no claim of cross-device leaderboard synchronization.

Keyboard and touch flow

On touch screens, tap a jug and then another jug to pour, or use the explicit pour buttons. Each jug also has Fill and Empty controls. On a keyboard, 1–3 selects a jug, F fills the focused jug, E empties it and H asks for a Verified Hint. Undo and Redo make it safe to explore alternative branches without restarting the date.

Pause stops the local timer and locks both jug input and solver tools. The exact numeric amount is always printed inside each jug so the result never depends on visually estimating the water height.

How the Daily calendar is verified

The release verifier does not trust the browser core’s precomputed answer. It independently implements the legal Fill, Empty and Pour transitions, then solves each selected state by breadth-first search. For the current bank it rechecks all 90 frozen sources and all 420 jug-order permutations before validating thousands of seeded Practice calls and every date in the 2026 Daily sequence.

That process verifies both solvability and metadata such as shortest distance, shortest-path count and explored-state count. It also confirms deterministic selection: asking for the same Practice seed or Daily date twice must return the same puzzle identity.

Using Daily as a learning loop

A useful routine is to solve once without solver help, then replay if you finished above par. On the second run, look for the first operation where Detour overhead became positive. That point usually reveals the planning mistake more clearly than simply reading a finished solution.

If you are completely stuck, take a Verified Hint and study why that move reduces the exact remaining distance. Assisted runs still count as completed learning sessions; they are simply kept separate from Clean personal-best evidence.

Practice when one puzzle is not enough

The Daily is intentionally one date-stable challenge, not an unlimited feed. Practice is where you can request fresh seeded puzzles across Easy, Standard and Challenge, replay exact URLs and compare how different capacity sets change the reachable state graph.