Bowser Door Manip

SMRPG's RNG counter only runs in world areas. It does not run on the overworld map. 

Therefore, we are able to save in places that have very easy, not-very-variable movement to a nearby exit, and go right to Bowser's Keep, where the door order is set upon entry.

Mario's Pad Manip - Very Easy (All Versions)

Mario's Pad Manip is free. It is very difficult to do it incorrectly.

After returning to Bowser's Keep, leave immediately and return to Mario's Pad (pass Vista Hill on your right now that the world map has been reconnected).

Save at Mario's Pad and then soft reset (L + R + Start + Select)

Hold Y, down, and right, then do a quick down input (OR hold Y and Down, and then Y+Down+Right when you reach the end of the trees before the exit) to manipulate Battle Doors to 3 & 6.

The isometric nature of the game makes it not really matter too much when you switch between down & down+right.

Go to Bowser's Keep. DO NOT ENTER VISTA HILL!

Once you get to the bowser doors, the doors you want are 1, 2, 4, and 5.

Monstro Town Manip - Very Easy (All Versions)

There is currently no use for this in any%, however this may be used in Most of the Stuff.

This is even easier than Mario's Pad manip. Save at Monstro Town and then soft reset (L + R + Start + Select).

Hold up and right, and leave to the overworld map.

Go to Bowser's Keep. Once you get to the bowser doors, the doors you want are 1, 2, 3, and 6.

Nimbus Manip 

Nimbus Manip is ~16 seconds shorter than Mario's Pad Manip, but is much more difficult.

Nimbus Manip has only been tested on SNES. Nimbus Manip audio cues are not reliable on most emulators due to music syncing issues. Attempt at your own risk. 

After the short cutscene with Mallow's parents following Barrel Volcano, go back to the save point near where you escaped Dodo's statue minigame and save & soft reset (L + R + Start + Select)

Reload your file.

In the save room, run left.

In the next room, run left,

In the main hallway, run down-left.

Outside the castle, run left until you hit the corner, then run up-left.

In the bus area, run up and up-left and talk to the bus mechanic immediately.

You can choose one of 3 version of the manip in this room, according to which frame windows you are the most comfortable with.

Easy (Japanese version)

Here's how it looks in action.

(video credit: Lack)

The frame window is determined with an audio flowchart: 

If you're not comfortable with audio cues or reading sheet music, follow Claude's setup video which explains a supplementary visual cue.

Go to Bowser's Keep and do not leave. Proceed to the 6 doors.

Each of the 7 frames you can clear the text box in has a different arrangement of doors that can be determined with the flowchart shown above.

Text version of flowchart:

If you missed the 7-frame window, you can use the chart below to figure out which frame you hit it on and act accordingly.

Easy (English Version)

The frame window is determined with an audio flowchart: 

There is no known supplementary visual cue for this version of the manip, so it is not recommended to attempt it unless you are very comfortable with parsing sheet music to use audio cues.

Go to Bowser's Keep and do not leave. Proceed to the 6 doors.

Each of the 8 frames you can clear the text box in has a different arrangement of doors that can be determined with the above flowchart.

Text version of flowchart:

Moderate (Japanese Version)

Credits to swinch.

This is 70 frames faster than the Easy Version, and gives you a better setup for the Factory Wrong Warp.

It is similar to the Easy Version, but the frame window is a bit tighter.

This video showcases a pretty easy visual cue. Another one is shown below:

(video credit: Claude)

swinch has also created a full tutorial video for this version of the manip, as well as a pastebin describing it in great detail (this version is called "Method 2" in the pastebin).

The door flowchart is documented below.

Text version of flowchart:

Difficult (Japanese Version)

Saves ~140 frames over the Easy version.

swinch has created a full tutorial video for this version of the manip, as well as a pastebin describing it in great detail (this version is called "Method 1" in the pastebin).

This requires both optimal movement getting to the Royal Bus, as well as either a turbo controller or very good text advancement. This is the fastest known method, and also guarantees the Wrong Warp regardless of which frame you enter on.

Text version of flowchart: