Secret Grade Techniques

"Secret Grade" is a hidden grading mechanism in the TGM series that rewards creating a ">" shape by leaving holes in the stack. At game over, the game evaluates the blocks in the field, looking for a zigzag pattern, and it awards a "secret grade" depending on how much of the pattern is completed. TGM's detection requires that the pattern is started from the bottom-left.

Grading
The player is awarded a secret grade for every row of the pattern completed. A row is considered complete when all cells in that row are filled, except for the empty cell required for the pattern.

General Tips

 * Maintaining an even spread of pieces throughout the stack is very important. Uneven stacking can hinder the completion of holes and reduce placement choices near the top of the stack. Placement choices are limited near the top of the stack, so care should be taken to maintain an even stack without obstructions.


 * If it appears that the stack is growing unstable, the best strategy is to clear lines or backtrack until a stable approach can be made.

Starts
Starting the structure can be efficiently started with any piece but O. At least one line clear is required when using any other piece, but using O to create the first hole necessitates two.

Reversing the Stairs
Reaching the right wall is like starting over again; a line clear structure is needed to create the first few holes. Structures going to the right wall can be reused when returning to the left, but the pieces used must be flipped. For example, structures that used L before reaching the wall now use J on the return trip.

Base
Main Article: Secret Grade Base Setups

Covers
Main Article: Secret Grade Cover Setups

Line Clear
Main Article: Secret Grade Line Clear Setups

Finishes
There are very few ways to complete the pattern. The 19th hole must be covered in order to qualify for the Gm grade. For this reason, the successful completion of the pattern is dependent on receiving specific pieces depending on the current state of the stack.

The safest way to finish the pattern is to cover the sawtooth at the top with a Z, simultaneously finishing holes 18 and 19. After placing the Z, you can then proceed to fill the rest of row 19.

Riskier methods will depend on receiving one or more I blocks precisely when they are needed. An I block can spawn and move freely in row 20, enabling it to be used as a cover for the incomplete pattern.

An even riskier method involves placing a T flat over hole 18, clearing row 19, and covering hole 19 with a J.

Keep in mind that the piece that causes the game to end can also complete the pattern.

When making considerations for a potential GM solution, it may be advantageous to place L, J, and I blocks vertically on the right side of the field as you approach the top of the field. Several vertical placements of these pieces will work in parallel to fill multiple rows while leaving the spawn area open for new pieces. On the other hand, horizontal placements in the center or on the left may reduce mobility or occupy part of the spawn area.

Tetris Best 2
The > sign technique from TGM3 also applies to Tetris Best 2, but is much more difficult to exploit due to the difficulty of clearing the garbage and then getting the right configuration. However, pieces you don't like can be destroyed with hold.