The first escape room that you will come across in Nine Hours, Nine Persons, Nine Doors is the 3rd Class Cabin. This room will serve as your introduction to how puzzles work in the game, allowing you to get a feel for the basic game mechanics. While in this room, your ultimate goal is to find an escape and leave.
In this guide, we are going to go over how to successfully escape the 3rd Class Cabin. Since this is the first room in the entire game, we will not go over any bits of information that could potentially spoil the story. First, let's take a look at the layout of this small room.
3rd Class Cabin Layout
The 3rd Class Cabin is relatively small, but it is packed with items. On either side of the room, you will find a three-layer metal bunk bed with a thin mattress and blue-striped blanket.
In the back of the room, you will find a table with a porthole that is pouring out water, and a sink to the side. Across from the table, there is also a small closet.
The porthole will let water into the room as you try to escape, but this does not have an effect on how much time you have to escape. Although Junpei is stressed about being trapped in a room that is filling with water, you can take as much time as you want.
Lastly, you can find a covered mirror hanging on the wall directly next to the door with the number '5' painted on it.
How To Escape The 3rd Class Cabin
It's now time to make your first escape. First, face the mirror and remove the cover; doing so will reveal a red key taped to the middle. Grab this key and add it to your inventory. Since this is your first time escaping a room, several tutorial screens will appear when you do something for the first time, such as adding an item to your inventory.
Back away from the mirror and look towards the tea kettle near the closet in the back of the room. You can open this kettle to retrieve the blue key. On the stove below the tea kettle, you can find a screwdriver as well.
Across from the kettle, you can see a bulletin board with an image of a ship below it. Grab the ship image, as well as the note with triangles pinned to the board, and add them to your inventory.
Now, look at the beds in the room. You should see a locked blue briefcase on one. Look to the bed opposite the case and check underneath; you will find a piece of paper with four shapes, similar to the one from the bulletin board.
Combine the ship picture and the screwdriver to open the frame. On the backside of the image, you will see a variety of shapes with numbers above them. This is a hint to open the briefcase.
Open the closet curtain to the left of the kettle to reveal a locked red briefcase. Using the back of the ship picture and paper from the bulletin board, you can enter the correct passcode to the case.
Read the red shapes in order, and you will get the code, which is 7485. Once this is entered, use the key to open the case. Inside, you will find a stack of red keycards that will be added to your inventory.
Now, it's time to open the blue briefcase. The code for this case will be based on the blue shapes from the two memos, with the correct code being 0263. Inside the case, you will find a file, explaining how to find the digital roots of numbers. Attached to the back of the file, you can find a stack of blue keycards.
Finally, it's almost time to escape. Head over to the door and take a look at the keycard reader. Interacting with the reader will begin a puzzle, where you need to find the digital root of the number on the door. Digital roots are found by finding the sum of digits until one remains.
So for this puzzle, you need to find a number that has a digital root of 5. When adding the digits of 14 together (1 + 4), you get 5, which is the number we are aiming for.
With this in mind, you now just need to find three cards that total 14, which has a digital root of 5. The correct cards that you will need are 1, 6, and 7.
Add these cards to the spaces in the puzzle, and you can make your escape!