1. Select the magnifying glass from your inventory and press the Japanese flag (the one with white and a red circle in the middle) to reveal the clue.
2. Press the block piles in the following order: First pile: 1 time Second pile: 4 times Third pile: 5 times Fourth pile: 1 time
3. The first pile should have 2 blocks, second pile should have 5 blocks, third pile should have 6 blocks, and the fourth pile should have 2 blocks. Press the door to open it.