Onet is a name for the flat, single-layer connecting board: identical tiles vanish when you can draw a path between them that bends no more than twice. The word is not a rule, a publisher or a variant. It is what this format is called in Indonesia, where the boards were popular enough that the local name travelled back out into search results everywhere else.
Where the name came from
The format itself is Japanese in origin, sold under the name shisen-sho since the late 1980s in arcades and on home computers. What spread across Southeast Asia in the 2000s was a wave of desktop and web clones, many of them using animal or cartoon artwork rather than tile faces, and the ones that landed in Indonesia carried onet in their titles. The name attached itself to the format rather than to any one program.
Vietnam did the same thing with a different word, calling the boards after the cartoon creature printed on the most popular clone. So a search for onet, a search for shisen-sho and a search for that Vietnamese name all lead to boards with identical rules and different pictures. None of them is the original and none is a knock-off of the others; they are regional names for one puzzle.
The two-turn rule, precisely
Two tiles clear when all three of these hold. The faces are identical. A path exists between them made of horizontal and vertical segments. That path changes direction at most twice, and every square it crosses is empty.
The third condition is where beginners lose time, so it is worth unpacking. A straight line between two tiles is zero turns and always legal if the squares between them are empty. An L-shaped route is one turn. A route that goes out, along and back in is two turns, and that is the limit. Anything needing a third bend is illegal no matter how obvious the pair looks.
One detail rescues far more boards than players expect: the path may leave the grid. It can run along the outside edge and come back in, which means two tiles on opposite borders are often connectable even when the middle of the board is solid. Programs differ slightly on how far outside the edge a path may stray, but the outer lane is available on nearly all of them. A layout of that kind in the catalogue here is Mahjong Connect.
Why a board runs out of moves
A connect grid can reach a state where every remaining pair needs three turns. That is a dead board, and it is not a mistake you made twenty moves ago. Most implementations detect it and reshuffle what is left in place, some let you trigger the shuffle yourself, and a few simply end the level. Because the format rescues itself this way, an onet board cannot be quietly lost the way a stacked layout can, which is the main reason people who dislike solitaire dead ends prefer it. The comparison of the two formats goes into that difference properly. Kris Mahjong is one of the layouts kept on this site.
Onet, Kyodai, link, chain and shisen-sho
All five words describe the same rule set. Shisen-sho is the Japanese original name. Onet is the Indonesian one. Kyodai came across from a long-running Windows package that popularised the format on desktops and now appears on browser boards that have nothing to do with that program. Link and chain are what publishers write when they want a title in plain English. The site’s own example of it is Butterfly Kyodai HD.
The genuine differences between boards in this family are not in the names. They are in the timer, whether levels carry over lives, whether a hint button exists, whether the grid is a plain rectangle or a shaped outline, and how many tile faces are in play, since a board with few distinct faces is far easier than one with many. The plain onet board in this catalogue is a straightforward version to test those things on.
What the artwork changes
Onet boards drifted away from tile faces early, which is why so many of them show animals, fruit or cartoon characters instead of bamboos and circles. That is not decoration alone. A grid you scan under a timer is read by shape and colour, and a set of twenty brightly separated pictures is far quicker to sort visually than a set of traditional suits where the difference between a four and a five of circles is one small ring.
The practical consequence is that a themed onet board is usually easier than a plain one at the same grid size, and a board using proper tile faces is the honest test of your speed. Grid size matters in the same direction: a wide grid with many distinct faces leaves few duplicates near each other, so the outer lane does most of the work early on.
Some boards also add a hint that highlights a legal pair and a shuffle you can call yourself. Both usually cost points or seconds, and the shuffle is the more useful of the two, because a hint solves one pair while a shuffle changes every remaining position at once.
How to open a jammed board
Clear from the edges inwards. Tiles on the outer ring can almost always reach each other along the outside lane, and removing them widens the corridors for everything trapped in the middle, whereas taking a convenient pair out of the centre often does nothing for the pairs around it.
Scan by face rather than by position. Pick one picture, find all its copies, and check them against each other before moving on; hunting visually across the whole grid is slower and misses the pairs sitting two rows apart. And when the timer is short, take the obvious adjacent pairs first rather than solving the hardest connection on the board, because a level ends on the clock, not on elegance.
The connect section holds these boards under every one of their names, and the map of Mahjong types shows where the flat grid sits next to the stacked and rotating formats. If you want the short tour of what else you will meet online, the three-format overview covers it.
