The short version
Tigadi is played on the twelve men’s morris board — the standard three rings plus four corner diagonals — but with nine pieces per player, and a piece never gains the ability to jump.
That single sentence is the whole difference. Everything below is the detail behind it.
Difference one: the board has diagonals
The standard nine men’s morris board is three concentric squares joined by four spokes through the midpoints of the sides. It has 24 points and 16 lines that can hold three pieces.
Wikipedia describes twelve men’s morris as the variant that "adds four diagonal lines to the board and gives each player twelve pieces". Tigadi takes the first half of that and not the second: the four corner diagonals are present and playable, but each player still has nine pieces.
| Nine men’s morris | Twelve men’s morris | Tigadi | |
|---|---|---|---|
| Points | 24 | 24 | 24 |
| Corner diagonals | No | Yes | Yes |
| Lines that can hold three | 16 | 20 | 20 |
| Pieces each | 9 | 12 | 9 |
| Flying at three pieces | Usually | Usually | Never |
The extra four lines change the board more than the number suggests. On a board without diagonals every point sits on exactly two lines. Add the diagonals and the corner points sit on three, while the side midpoints still sit on two — so the board stops being uniform, and the corners become the valuable squares.
Difference two: no flying, ever
Most published morris rules give a player reduced to three pieces the ability to move a piece to any empty point on the board, rather than one step along a line. It is variously called flying, hopping or jumping.
In Tigadi that never happens. A goti steps to an adjacent point along a drawn line at every stage of the game — with nine pieces, with three, with two.
This is not a house rule invented here. Wikipedia notes of the flying rule that "some rules sources say this is the way the game is played, some treat it as a variation, and some do not mention it at all." No-flying is one of the documented positions, not a deviation from a settled standard.
The consequence is that the endgame plays completely differently. With flying, a player down to three pieces can break any developing tigadi anywhere on the board, and the game tends towards a draw. Without it, position and mobility keep mattering right to the end — a trapped piece stays trapped, and a well-placed tigadi cannot be answered from across the board.
A smaller difference: blockade is not a loss
Many morris rule sets, including several traditional Indian descriptions, end the game against a player who has no legal move. In Tigadi that player simply passes and play continues.
This is safe rather than arbitrary: the board is connected and every point has at least three neighbours, so two players can never be stuck simultaneously. A pass always returns the turn to somebody able to move.
A note on the oldest boards
There is a pleasing footnote to the diagonal question. The boards most often cited as the earliest morris evidence — cut into roofing slabs at the temple at Kurna in Egypt — are described as including diagonal lines. R. C. Bell dated them to around 1400 BCE.
That dating is disputed, and properly so: Friedrich Berger observed that some of the Kurna diagrams carry Coptic crosses and concluded that "certainly they cannot be dated". So this is not evidence that the diagonal board is the older form. It is only a reminder that boards with diagonals have been around for as long as anyone has been arguing about morris boards at all.
Common questions
Is Tigadi the same as twelve men’s morris?
It uses the same board, but not the same game. Twelve men’s morris gives each player twelve pieces; Tigadi gives nine. With nine pieces on a 24-point board there is far more empty space, so the placing phase is a contest for the strong points rather than a scramble to fit everything in.
Why remove flying? Doesn’t it make the endgame unfair?
It makes the endgame decisive rather than fair-in-the-sense-of-drawish. With flying, a player down to three pieces can answer any threat anywhere, and well-played games tend to peter out. Without it, an advantage earned in the middle game actually converts, and being blocked is a real cost you have to play around.
Which version is the “correct” one?
Neither. Morris is thousands of years old and has no governing body; the rules vary by region and by century, and even the flying rule is treated as optional by many sources. Tigadi is one coherent, consistently applied set — stated in full so you know exactly what you are playing.