Tutorial Video

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The Basics

Kaidan is a T-spin double setup created using a vertical S or Z as a prop to make its base:

Diagram Set 1-1

Kaidan’s main purpose is to save Ts by minimizing T wastage in the stack:

Diagram Set 1-2
1	2

This sequence shows a typical way to make a T-spin double by wasting a T in the stack.

Conversely, you could do this to save a T piece for the actual T-spinning:

Diagram Set 1-3
1	2

This shares the same starting condition as diagram set 1-2’s step 1. A player does not waste a T piece in the stack.

Hence, by using a Kaidan, you might resolve the field unevenness issues without wasting a T in the stack. Therefore, Kaidan T-spins are excellent.

Common Mid-Game Chances

Kaidan is incredibly versatile, having many mid-game situations besides stair-like patterns.

1. Stair-Like Situations

When one first learns to use Kaidan, it is easiest to start by spotting a stair-like pattern in 9-0 stacking (the garbage hole is in the far-left-most or far-right-most column).

Diagram Set 1-4
1	2

Recognize this stair-like mid-game pattern (in lavender blocks) during 9-0 stacking.

Put a vertical S and make an overhang for a Kaidan T-spin double.

Once you have familiarized yourself with the above method, you can transition to where the main Tetris hole is in the mid-lane:

Diagram Set 1-5
1	2

You can make mid-game Kaidans in the mid-lane by spotting a stair-like pattern.

This subsection’s 2 methods are the most commonly used in making a Kaidan.

2. Fixing Height Imbalances

Kaidan is mainly used to fix a height imbalance issue in the following cases:

Diagram Set 1-6
1	2

A starting field with uneven stacks left and right of the garbage hole in column 5.

The player places a vertical T to balance both sides of the field, making the T-spin doubles again. However, placing a T is inefficient and may lead to a T drought.

Alt. A

This shows a Kaidan resolving this without putting a T in the stack. This increases one’s efficiency.

3. S/Z Prop

A sub-variant of Kaidan is the S/Z T-spin prop. I categorized them under the same technique because it is so similar to traditional Kaidan. Here are common mid-game situations to use it:

Diagram Set 1-7
1	Alt. A

See how the left and right stacks of column 4’s hole differ in height by 2 blocks. The player has 2 choices.

The player can easily put the vertical S to create a T-spin double base and finish it with an overhang.

Alt. B

The player can make a horizontal Z placement to create a T-spin single!

If the player is astute, he will recognize these as the beginning foundations of a Hamburger and ST stacking sequence, explained in The Easiest T-spinning Methods chapter of Book 2.

Continuations and Follow-Ups

Kaidan is excellent as it is straightforward and can be followed up with mid-game ST stacking, Yoshihiro T-spins, and many other methods later. Here are some follow-ups:

1. Kaidan to ST Stacking

Kaidan can lead to ST stacking, a common T-spin double spamming method.

This is easiest if the garbage hole is in the third or eighth columns.

Diagram Set 1-8
1	2

3

4

The player starts with a Kaidan prop to a T-spin double. This then leads to ST stacking.

2. Kaidan to Yoshihiro

Kaidans can easily lead to Yoshihiros, especially in 9-0 stacking scenarios:

Diagram Set 1-9
1	2

This method involves completing a usual Kaidan T-spin double during 9-0 stacking.

The T-spin double line clear concludes.

3

4

The player makes a T-spin mini with the Yoshihiro method.

He tops the newly formed T-shaped cavity with an overhang (lavender blocks) to make a new T-spin double.

3. Following Up T-Spin Triples with Kaidans

Kaidans can follow up certain T-spin triples cleanly:

Diagram Set 1-10
1	2

A useful application of Kaidan is to easily follow up on T-spin-triple-like setups. The above is a normal T-spin triple. The lavender overhang is 2-blocks-thick.

3

4

Something interesting happens after the T-spin triple when the lavender overhang is 2 blocks high: you can follow up with a clean Kaidan T-spin without using soft drops!

Here is an actual mid-game sequence:

Diagram Set 1-11
1	2

This shows a T-spin triple setup.

The T-spin triple line clear concludes.

3

The player puts a vertical Z to make a Kaidan.

See how clean it is? Back-to-back bonus is also sustained using this method!

This method can save an extra line clear from having to skim off the dirty overhang left by a T-spin triple.

It also may save some soft drops from tucking a piece to fill the cavity under the T-spin triple’s leftover overhang.

Advanced

Kaidans have advanced variants, such as non-linear and complex prop variations.

1. Suspensions & Complex Donations

Kaidan can be used in more advanced ways by suspending the lavender parts cleanly over holes, like below:

Diagram Set 1-12
A	B

Notice that there are no dirty places on the lavender parts? After the line is cleared, you get a clean field.

This is extremely difficult, and I encourage players to experiment.

2. Non-Linear Construction

Kaidans can also be constructed out of order:

Diagram Set 1-13
1	2

The above places the S (as the base) first before constructing the right side, without needing a stair-like mid-game pattern.

Hence, Kaidans can be created nonlinearly by constructing the overhang or the base in either order. Here are a few more examples:

Diagram Set 1-14
1	2

The starting field with a Kaidan opportunity.

The player first builds an overhang with L and Z pieces.

3

He later puts the vertical S as the Kaidan T-spin double’s base.

Doing this comes with experience. 

Here is a more advanced execution:

Diagram Set 1-15
1	2

No immediate Kaidan opportunity seems to exist.

However, the player puts a vertical Z to create the base.

3

Then, he constructs the right side and overhangs simultaneously to make the Kaidan T-spin double.

Therefore, Kaidans can be built out of order by expert players.

A Kaidan’s overhang can also be forecasted in this common situation:

Diagram Set 1-16
1	2

A T-spin double exists.

The player puts a Z overhang on the right side first.

3

4

The T-spin double concludes.

The player puts a vertical S, creating a forecasted Kaidan.

In a Nutshell

Overall, Kaidans are among the most practical and versatile mid-game T-spin setups. This is why I have made this the first chapter: learning just this one method heavily expands your T-spin foresight.

Pros and Cons
Pros	Kaidan leads to high back-to-back T-spin double chaining continuations. Its mid-game stair-like pattern happens frequently. It can balance both sides of the stack, preventing T wastage.
Cons	Blocking the Tetris hole may make you vulnerable to spikes.