Practice
Practice sets.
Twenty-four rivers with no date attached, three sets per level. They never change, so you can come back to one, and they do not touch your daily streak. Your progress in each set stays in this browser.
Easy.
Five by five. Every river here can be solved with the simple local steps Hint knows: a 0 crossing all four of its sides, a 3 in a corner using both outer sides, and a dot that already has two lines crossing the rest.
Medium.
Six by six. The pattern rules join in: two 3s side by side, a 3 sitting next to a 0, a line arriving at the corner of a 1 or a 3. Still nothing to guess.
Hard.
Seven by seven. The hardest rivers lean on the short-loop check and a one-step trial: try a side, see where it leads, take it back if the numbers cannot agree.