Not possible.
Triple Checkmate

It is not possible, you can only have a double. I would go into all of the details, but they are boring and long. Basically you can only use one discovery and not two and a check.

It is not impossible. I have done it. It takes time to set your opponent up.
It can only be done with a knight, when you put the king, queen and castle in check with the same move.
Bon Appetite

It is not impossible. I have done it. It takes time to set your opponent up.
It can only be done with a knight, when you put the king, queen and castle in check with the same move.
Bon Appetite
Nice but this is not a triple checkmate. It is a triple double attack from a Knight to a King A Queen and a Rook.
And a check not a double check.
A double checkmate would be for example.
Or also

Unless you are playing Chinese chess, which probably allows a quadruple check, but I am not sure if checkmate by triple check is possible or not. It should be.
In international chess, however, this is not possible.
Unless you are playing Chinese chess, which probably allows a quadruple check, but I am not sure if checkmate by triple check is possible or not. It should be.
In international chess, however, this is not possible.
never possible!

Oh sorry I meant B-g6
no thats not quadruple its only double because there are only two pieces actually checking the king


There is only one way I could think of a triple checkmate is possible and that is with a illegal move. Imagine that you move the two knihgts from e3 and f6 at the same time in de direction of g4. The knight on e3 with your right hand and the knight on f6 with your left hand. Then when they arrive on g4 imagine they transfrom into one single knight that give checkmate on g4 and discover the diagonal from the bishop and the line of the rook in one move.
Thus the right hand with the e3 Knight you put on g4 and the lefthand with the f6 knight you hide in you handpalm and then put behind the clock and then press the clock and yell checkmate!
With somewhat different chess rules it is easy to get to a triple check. Notably fruitful is the Madrasi type where pieces of the same type attacking one another in standard chess, actually freeze one another!
For instance a white bishop on b2 and a black bishop on d4. Neither can play until one bishop is captured or a piece appears on c3. Not only easy to achieve triple check, also easier to get out of it. A king under double check in standard chess must always move, but a king under triple check in Madrasi can sometimes stay on its square when his side freezes and interferes the 3 attackers all by one move.
Is it possible? Can anyone advise?
Thanks.