River Crossing IQ · Meet the game
Meet River Crossing IQ: familiar riddles, a new journey
Two jugs. One exact amount. A boat that has to come back. Discover 42 handcrafted puzzles with Sen, now on the App Store for iPhone and iPad.
A three-litre jug. A five-litre jug. No measuring marks.
Can you leave exactly four litres in the larger jug?
You can fill, empty and pour. The rules fit in a sentence, yet the answer might have you mentally moving water between containers before you reach the end of this paragraph.
That is the kind of small, absorbing challenge at the heart of River Crossing IQ, our illustrated puzzle adventure for iPhone and iPad. Follow Sen through a countryside of rivers, gardens and lotus ponds, and explore 42 handcrafted puzzles across seven chapters.
River Crossing IQ is available on the App Store. Every level is free to play, including offline; the game includes ads and optional in-app purchases.
Classic logic riddles, told as a story. Start with an idea, try a move, and see what changes.
A familiar question can still surprise you
Some puzzles feel instantly recognisable. You have seen two water jugs before. You understand what a boat does. You know that a bridge connects one place to another.
The interesting part begins when a constraint changes the obvious plan.
In the water-jug puzzle, getting close to four litres is not enough. Each pour has to leave you with something useful for the next step. Rather than rushing towards the final amount, try asking a smaller question: what amount would make the last pour possible?
We will leave the answer for you to discover in the game.
The journey back matters too
A river-crossing puzzle seems to have a simple goal: get everyone to the other side. But the boat has to return, and the bank you leave behind matters just as much as the one you are heading towards.
One of River Crossing IQ’s garden challenges gives you three sprouts, three jars and a boat carrying one or two items. On either bank where there are sprouts, jars must not outnumber them. Jars on their own are safe.
It is a small set of rules with an intriguing consequence: moving closer to the destination is not always the same as moving closer to a solution. Sometimes the useful move brings something back.
Before you tap Go, take a look at both banks. What will your next trip need?
More than river crossings
Across seven chapters, the questions change. Water jugs ask you to reason about quantities. Bridges ask you to plan a route. Number puzzles turn order into a clue. Mosaics invite you to think about shapes and the spaces they leave behind. Later challenges include rolling stones and new ways to read the board.
This variety is part of the journey. A method that helped with one puzzle may give way to a different way of thinking in the next. You are exploring a collection of problems, each with its own rules and goal.
The lotus mosaic is a good example. Seven pieces must find their places on a grid. You can rotate them, but not flip them. A piece that fits now can still leave an awkward space later—so the empty parts of the board are clues too.
A story around every problem
Sen’s straw hat and red scarf accompany you through a world inspired by the Vietnamese countryside. Rivers, green hills, village scenes and lotus ponds give the puzzles a shared setting, while short stories add a reason to keep travelling.
You do not need to know the setting or arrive with a collection of memorised solutions. The stories and illustrated rules are available in English, with Vietnamese also supported in the game. Read the goal, look at the board and try your own approach.
The calm artwork leaves the puzzle in focus. Whether you enjoy an exact sequence of moves or a shape that finally clicks into place, there is a different kind of discovery waiting along the route.
Try an idea, then reconsider
Undo gives you room to change your mind. Progress is saved automatically, so you can return to a problem after a break. When you want a little direction, Solve with Sen provides guidance; specific hints use stars.
All 42 levels are free to play offline. Purchases and online services need an internet connection. Optional Game Center and iCloud features support saved progress on Apple devices; you can begin with the puzzles without making those features the centre of your experience.
What is free, and what is optional?
You can play every level without buying a level pack. River Crossing IQ includes advertising and optional in-app purchases: star packs for specific hints and a purchase that removes automatic ads. Rewarded ads remain optional.
Current pricing and purchase details are shown in the game and on the official App Store listing. For help, visit our support page; you can also read the privacy policy and account and data deletion guidance.
Your next move is waiting
Start with two jugs, or a boat and a pair of riverbanks. Read the rules. Try the move that seems right—and see what it leaves behind.
River Crossing IQ is available now for iPhone and iPad.
A little thought. A new journey.
Your next move starts here
Play River Crossing IQ
A little thought. A new journey.
Free to play · Ads & optional purchases
Official store downloads · Available in supported regions