Gamushiro Stacking (ガムシロ積み)

Gamushiro Stacking is a TST → TSD (or TSS) → PC opener created by KMGZ. ガムシロップ translates to Gum Syrup.

Bag 1

It's possible to build this for all opening bags.

Bag 2

You won't be able to stack your second bag this way every time, but you should be able to for the majority of your bags (66.67% chance). See below for some alternative ways of stacking your second bag, but this is the most preferred shape.

Bag 3 (PC)

These are the 6 solutions that you'll want to know. You'll have a 78.35% chance of being able to PC with these, but if you can place the T first, you'll have a 92.22% chance.

The field itself has a 99.09% PC chance if you learn all the solutions. Look here for all solutions.

3巡パフェ後テンプレ

TSD → PC setups that you can use after performing an 8-height PC

Early O

Getting an early O in your second bag is the most common reason for needing to stack your second bag differently. This section shows some alternate patterns that you can use while still preserving a good PC chance. They are ordered by preference. You'll be positioning your L from your first bag slightly differently for each pattern.

Holding L

Holding the L from your first bag will sometimes allow you to stack in a way that makes the same shape shown in the previous section. You'll be able to stack either the original form or this way 83.33% of the time.

Alternate Pattern 1

You'll stack your first bag the same way, but you'll be positioning your O differently on your second bag. This pattern will help you cover 91.67% of bags.

The overall PC chance is 96.94%, and here are the solutions. If you can place the T like below, you'll have a 92.22% chance with 6 solutions.

Alternate Pattern 2

credit to GenDragFan

Another way to stack when you spot an early O in your second bag would be placing your first and second bags like below. It brings up the stacking probability to 94.72% in official clients and 96.67% in unofficial clients with 180 rotations.

This is good in unofficial clients with 180 rotations because you can also place the S first and then spin in the L afterward, which makes it possible to stack this way in many second bags with an early O.

The overall PC chance is 93.06%. Look here for solutions. You'll have a 100% PC chance with 2 solutions if you can place the T as shown below.

Alternate Pattern 3

This pattern should work most of the time if all of the above fails. It brings up the cover chance to 98.06% on official clients and 100% on unofficial clients with 180 rotations.

credit to JimothyJimothy

multiple discovery by metallicLurker and PandaEDIT158

There is a high PC chance (96.71%), and you can look up the solutions here. If you can place the T, the chance is 100%.

Other

Otherwise, just freestyle your second bag. For example:

As a side note, the pattern below will bring up the cover chance to 100% in official clients. The overall PC chance is lower at 83.69%, but it becomes 100% if you can place the T. Here are the solutions.

credit to metallicLurker

FOUR