Quoting myself from this post on speedsolving.com:

I’d like to introduce my notation for NISS solves, because I find it easy and practical. If you like it, we can use it (or something similar) as standard notation

The rule of thumb is: a ‘(‘ means “switch to inverse scramble using the inverse sequence of the moves found for normal scramble as premoves”, a ‘)’ means “switch to normal scramble (…)”. An example will make it easy for everyone to understand:

**Scramble:** R2 F D2 F’ R2 B’ D2 B’ F’ L2 F U’ F2 L’ U2 B R’ F D2 F D’

**Solution:** L2 D’ L2 R B L F’ L’ F R’ U2 F’ U F U2 F U F’ U’ R’ F’ L F L’ F’ R2 F2 R2 (28 HTM)

**Solution (written without this notation and with comments):**

*On normal scramble:*

L2 D’ L2 *//2x2x1*

* On inverse scramble with premoves L2 D L2:*

R2 F2 *//Another 2x2x1*

* On normal scramble with premoves F2 R2:*

L2 D’ L2 *//Two 2x2x1*

R B R’ *//Pseudo 2x2x3*

*On inverse scramble with premoves R B’ R’ L2 D L2:*

R2 F2 R2 F R *//XX-cross + pair in slot*

* On normal scramble with premoves R’ F’ R2 F2 R2:*

L2 D’ L2 R B *//XX-cross -1 move + pair ready (5/5)*

L F’ L’ F R’ *//F2L -1 + pair ready (5/10)*

U2 F’ U F* //F2L (4/14)*

U2 F U F’ U’ R’ F’ L F L’ R *//LL (11/25)*

R’ F’ R2 F2 R2 *//Undo premoves, 2 moves cancel out (3/28)*

**With my notation:**

L2 D’ L2 *//2x2x1 (3/3)*

(R2 F2)* //Another 2x2x1 (2/5)*

R B R’ *//Pseudo 2x2x3 (3/8)*

(R2 F R) *//XX-cross + pair in slot (3/11)*

R L F’ L’ F R’ *//F2L -1 + pair ready, 1 move cancels out (4/15)*

U2 F’ U F *//F2L (4/19)*

U2 F U F’ U’ R’ F’ L F L’ R *//LL, 2 moves cancel out with premoves (9/28)*