River Crossing Puzzle

How to play the river crossing puzzle

• Move everyone from the near bank (bottom) to the far bank (top) by boat, without ever breaking the puzzle’s rules. The trick is choosing who goes together, and in what order.
• Tap someone on the bank to put them in the boat, and tap them in the boat to send them back ashore. Then tap “Cross” (or the boat itself) to row over. Everyone gets out on arrival.
• The boat can’t move on its own: someone has to row it, both ways. When only some characters can row, they wear an oar badge.
• A move that breaks a rule isn’t allowed. The reason appears above the river, and whoever is in trouble gets a red ring.
• Each crossing in either direction counts as one trip. Solve a puzzle in the fewest trips to earn a ★ in the puzzle list. Timed puzzles are solved when everyone is across within the time limit.
• There’s a new puzzle every day, the same for everyone: a timed crossing with 4 to 6 people, with new crossing times and a new time limit each day. Some days the fastest person should ferry everyone; on others the two slowest should cross together. Open it with “Daily” at the top or from the top of the puzzle list.
• Stuck? “Hint” shows who to send next, and “Solve” plays the shortest solution from where you are (solves with the answer shown aren’t recorded — no ✓ or ★). Your progress is saved, so you can close the page and come back.

The 11 puzzles and their rules

How to solve river crossing puzzles

Each time someone rows back, check that the bank left behind still follows the rules. Some puzzles can only be solved by taking something back with you.

• River crossing puzzle solutionsWatch the fewest-trip answer to all 11 puzzles, one crossing at a time, with tips for wolf, goat and cabbage, bridge and torch, and the family puzzle

Where river crossing puzzles come from

River crossing puzzles are very old. Propositiones ad Acuendos Juvenes (Problems to Sharpen the Young), a collection attributed to Alcuin from around 800, already includes the wolf, goat and cabbage problem and a problem in which three brothers and their sisters cross in a small boat, a form better known as the jealous husbands problem. The “3 parents, 3 children” puzzle here follows that pattern.

The wolf, goat and cabbage riddle is also told with a fox, a chicken and corn (or beans). The sheep and wolves puzzles follow the classic missionaries and cannibals problem, with the same rule that one group must never be outnumbered. The timed puzzles are the boat version of the bridge and torch problem.

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