The Montenegrin stitch is an old stitch, it covers well and is good for general use. It can be done over two or four horizontal threads. My instructions will be for the smaller version.
The stitch begins by doing a diagonal stitch across four vertical canvas threads and two horizontal threads. Next step is to drop down once canvas two canvas threads below where you entered the canvas and then count to the left two canvas threads. Return to the front side of the canvas and go up two canvas threads and to the left two canvas threads before entering the canvas again.
In step number three return to the front side of the canvas in the hole where you came forward to begin stitch number two (that is, in the hole that is two canvas threads to the right of the beginning hole). Go straight up two canvas threads and return to the backside. Re-emerge out of the same hole (for the third time) and this time repeat step number one -- going up two canvas threads and forward four canvas threads. Repeat steps numbers two and three. The stitch consists of a repetition of this "go forward four, go back two, straight up, repeat." You are coming forward in the same hole three times.
The final result is a tweedy, ribbed texture that is similar to the long armed cross.