Bao rules

Bao is a two-player sowing game — a mancala — played on four rows of eight pits. You own the sixteen pits on your side of the board and your opponent owns theirs. A turn is one decision: which of your own pits to empty into your hand.

What makes it more than arithmetic is the relay. Seeds are sown one per pit, and if the last one lands where there were already seeds, you lift that pit and carry on sowing — so a single turn can run more than twice round your own sixteen pits and finish somewhere neither player was looking. Where it finishes is the only thing that can capture.

A game takes about fifteen to twenty-five minutes, with ninety seconds to make each move. It is a game of complete information: no hand, no deck, and nothing face down.

Thirty-two pits in four rows of eight. The two rows nearest you are yours; the two beyond them are your opponent’s.

Your outer row is the one under your hands. Your inner row is the one against the middle of the board, facing your opponent’s inner row across it. Captures happen only between the inner rows — in two of the three variants an outer pit can never be touched by your opponent at all.

One pit of your inner row — the fifth, counting from your own left — is your nyumba, your house. It is an ordinary pit in Maasai and the Long Game, sown through like any other. In Bank it is the pit the whole game is about.

• Two seeds in every pit. Thirty-two a side, sixty-four in total. There is nothing to deal and nothing to shuffle: every game of Bao starts from the position every other game of Bao started from. The one exception is Mid-game, the daily’s rule set, which starts from a Bao la Kiswahili game already in play.

• Pick a variant — Bank, Maasai or the Long Game. The board and the sowing are identical in all three; what changes is whether you can capture, and how you win.

• The first player moves. Both of you can see everything on the board for the whole game.

Choose one of your own pits that holds at least one seed, and take every seed in it. A pit holding a single seed is a perfectly legal lift.

Now sow them, one per pit, around your own loop of sixteen: along your outer row, then back along your inner row, and round again. The loop is closed and it is yours alone. You never sow into your opponent’s pits and they never sow into yours. The only thing in this game that crosses the middle of the board is a capture.

In Bank there is one exception to what you may lift: the house is never lifted. Every other pit on your side with a seed in it is a legal choice, in every variant.

Your hand running empty does not end your turn. Look at the pit the last seed landed in. If it already had seeds before that seed arrived, lift the whole pit — the new seed included — and keep sowing from there. Do that again as many times as it happens.

The relay stops the moment a seed lands in a pit that was empty. That seed stays where it is, and your turn is over.

This is why the opening looks strange the first time. Every pit holds two seeds, so in Maasai and the Long Game, whichever one you lift, the relay picks up and picks up again and sows exactly twenty-one seeds before it stops — more than a full lap of your sixteen pits. The pit you emptied is not empty when your turn ends: the relay came all the way round and dropped a seed back into it.

Bank is the exception, and only because of the house. A relay that comes to rest on your house stops there rather than lifting it, so opening lifts in Bank run anywhere from two seeds to twenty-one depending on where they land. The sowing itself is identical.

Apart from that, nothing about the relay depends on the variant. Bank, Maasai and the Long Game sow identically. They differ only in what happens where the relay stops.

Three things have to be true at once, and they are best learned as one sentence: your relay stops, in a pit of your own inner row, that was empty before your seed landed in it — and the pit straight across from it holds seeds.

When they are, every seed in that pit of your opponent’s comes off the board and into your store. They do not go into your pits and they never come back. The seed you landed with stays where it is.

If any of the three fails, nothing happens and your turn simply ends. Stopping in an empty pit of your outer row captures nothing. Stopping opposite an empty pit captures nothing. And a relay that passes over a capturing position without stopping there captures nothing — being mid-relay is not a capture, however inviting the pit opposite looks.

The Long Game’s second pit is conditional on the first. A loaded outer pit sitting behind an empty inner pit is completely safe, which is worth knowing from both sides of the board.

One engine and one table of rules make three games. They share the board, the setup and the relay exactly; each row below is the whole of the difference between them.

They are also an order, and it is the order to play them in. Bank teaches you where seeds go and how a relay runs, with nothing your opponent can do to you. Maasai adds the capture, which is the only thing in this game that crosses the middle of the board. The Long Game adds the pit behind it, and with it the habit of reading a whole column instead of a pit. Each one is the one before it with a rule added — and all three are a way in to the fourth, Bao la Kiswahili, which is the full game of the family and is described at the foot of this page.

All three names are ours, and none of them is the name of a traditional game — see “Where our version departs from the game as it is played” below. Bank has no captures at all, so neither side can touch the other: the two of you are running the same puzzle side by side. It is an exercise rather than a contest, and that is what it is for: it keeps no score, because there is nothing in it to grade, which is also why it is the one variant that is not on the ladder.

In Maasai and the Long Game you win the moment your opponent has no seeds left anywhere on their side — every one of their thirty-two captured. Nothing replenishes them, so the game is a grind rather than a sudden reversal, and it takes a long series of captures to finish one.

In Bank you win when every pit on your side except your house is empty, which means all thirty-two of your seeds are in it. Seeds enter the house one at a time as a relay passes, and are never lifted out again. You cannot be slowed down by your opponent and you cannot slow them down; you are simply the faster or the slower of two people doing the same thing.

A drawn game is a real result here and is recorded as one. See the no-progress rule below.

Sowing on its own is reversible: seeds travel a closed loop and come back. Two players who never capture and never bank can repeat a position forever, and in the Long Game that is not hypothetical — a simple enough policy reaches an exactly repeating position and then cycles through it for good.

So the game is called after fifty turns in which nothing irreversible happens: no capture, in Maasai and the Long Game, and no seed reaching the house, in Bank. Any capture resets the count to zero.

A called game is decided on what each side actually achieved — seeds captured, or, in Bank, how close your side is to empty. If those are level, the game is a draw, and it is recorded as a draw rather than awarded to somebody.

It rarely comes up. Almost every game ends by capture or by a filled house long before the count gets near fifty. The rule is here so that a rated match with a clock on it cannot run forever, not to hurry anybody along.

Everything. There is no hand, no deck, nothing face down and nothing hidden per seat: both players are looking at the same complete position, and so is anybody watching. Every pit count, both stores and whose turn it is are public.

That is worth stating rather than leaving to be noticed, because it changes how the game is lost. Nothing surprises you in Bao. Every capture that lands on you was sitting there, countable, for at least one turn before it happened.

• Lifting an empty pit.

• Lifting one of your opponent’s pits.

• Lifting your house, in Bank. It takes seeds and never gives them up.

• Stopping a relay early, or continuing one that has stopped. The relay is not a decision — it runs until a seed lands somewhere empty.

• Sowing the other way round the loop. The direction is fixed in all three variants we ship.

• Taking a capture you have lined up without landing on it. A capture is a consequence of where a relay stopped, never an action of its own.

Bao is an old and living game, played across East Africa, and no single written rule set is the authority for it. Three places where what we have shipped is a decision of ours rather than a transcription:

• The no-progress rule is ours. Over a real board a repeating position simply continues until somebody gets bored or plays differently, and nobody is counting to fifty. We count, because a rated match with a clock cannot be allowed to run forever — and because a position that has genuinely gone nowhere for fifty turns is better ended than left.

• The direction of sowing is fixed. The full Kiswahili game lets a player choose which way round to sow, which doubles the choices available on every single turn. In the three variants here there is one direction, and the only decision is which pit to lift.

• The variant names are ours, and none of the three is a traditional game. Bank, Maasai and the Long Game are labels we chose so that the variant buttons read at a glance. Until recently this page printed a Kiswahili name beside each of them as though it were the game’s own, and that was wrong three times over. Bao la Kujifunza, the game for learning, is played with captures and our Bank has none. Bao la Kimasai, the four-row Maasai game, begins with seeds held in reserve and placed over the opening turns, which we do not implement. And “Bao la Kimasai Mrefu” is not a game anybody has written down — we made the name up for the third rule set and then printed it in a column of names as if it were one. The rules on this page are the rules of what we have shipped; where a name here resembles a game you know, please do not assume the rules do.

None of this is hidden in the engine. If you find the board doing something this page does not describe, the page is the thing that is wrong, and it is worth telling us.

The full game of this family is Bao la Kiswahili, and it is the fourth rule set here. The three variants above are the way in to it: between them they teach the board, the relay and the capture, which are the parts of Kiswahili you can learn before you take on the rest of it. It is a different kind of position from theirs — seeds held in hand, a house that keeps a status of its own, and a turn that can stop to ask you something — which is why it is the last of the four rather than the third.

It is described here so that you know what the three above are teaching you towards, and so that a player arriving from that game knows straight away that they are not it. In Bao la Kiswahili each player begins with twenty-two seeds still in hand, six in their nyumba and two in each of the two pits beside it. The opening phase, namua, is spent placing those seeds one at a time, and you may only place into an inner pit that already has something in it — so a player whose own inner row is bare has no legal move at all, and loses on the spot with seeds still in their hand. Once the hand is empty the game becomes mtaji, where you lift from the board as you do here.

And a sowing that lands on your own nyumba, while it still counts as one, pauses the turn to ask you a question: sow those seeds onward — safari — or stop where you are. That pause is why this game is in the codebase at all. It is the one thing none of the three variants above does. A house stops counting as one for the rest of the game once it has been captured, lifted or sown onward at a safari. Until then you may place into it without a capture only when it is the last pit of your inner row with seeds in it, and then you sow just two of its seeds; and while it holds fewer than six it neither stops a sowing nor asks the question, until it holds six again.

If you came here to play Bao la Kiswahili, you can: choose it as the rule set, and ranked matches are played in nothing else. If you have not played this family before, Maasai is the closest of the three to it and the one to learn first.