The main application of this tech is to identify what subpixel string you may be on and help you determine type of wiggle may be required if you are utilising backwards walljump.
This is primarily useful for those wanting to go for the double framerule save in 1-2, as that requires a more aggressive first section compared to single rule save.
As you may already be aware a subpixel is used to determine Mario's position on a scale 1/16th smaller than a standard pixel, a subpixel string is a group of 8 subpixels (either 0-7 or 8-F).
At full speed, there are 5 possible subpixel strings, the Kaname Training Suite refers to them as strings 0-4.
The window of your walljump will depend on what subpixel string you are on, in 1-2 of SMB2J the windows for walljump are as follows:
| String | WJ Frames | Falling Animation | Koopa 3 Movement |
|---|---|---|---|
| 0 | 1 | Different | Jittery |
| 1 | 1 | Different | Smooth |
| 2 | 2 | Different | Smooth |
| 3 | 0 | Matches | Jittery |
| 4 | 0 | Matches | Smooth |
NOTE: Kaname Training Suite 3.7 has a bug where these subpixel strings will be off by one string (i.e. string 0 being rendered as string 4)
You can't know exactly what subpixel string you are on, but there are some context clues as to help you know what range of strings you may be on.
By doing a 1-frame flick on the ground just before falling to the lower section of 1-2, you can determine if you are set up for forwards walljump by checking if Mario's falling animation is not the same. If it is the same, you are on either string 3 or 4.
While the above information is useful for determining if you are set up for walljump pixel by doing a forwards walljump, you want additional information to help with determining what wiggle speed is required for backwards walljump.
This is achieved by looking at the third Koopa Troopa in the group of three on the ground. Koopa Troopas walk at 0.5px (one string) per frame and can either appear to move smoothly or jittery depending on Mario's subpixel string alignment relative to the Koopa's.
If the third Koopa is moving jittery, then you are on the lowest possible subpixel string for either walljump pixel being possible (string 0), or impossible (string 3). Unfortunately because of framerate issues this is impossible to showcase via a GIF and is more visible on displays that can output at the NES refresh rate of ~60.0988Hz.
If you see the third Koopa have jittery movement and you have two distinct falling animations, then you are not able to rely on a fast wiggle and will need to do a slower wiggle to get on a string that can get WJ pixel.
Normally people just hold right when performing a walljump, but depending on several factors such as Mario's position and subspeed that can determine if your walljump will be fast or slow. By releasing right and repressing it at a consistent point you can mitigate this variance in speed and reduce XPOS gained from tradition WJ methods to help load the Piranha Plant earlier.
