The **Abacus Puzzle** is a puzzle present in version 5.2 of Ao Oni. It is often noted for it being difficult for non-Japanese players due to it being a traditional Japanese puzzle. It is accessible after solving the Length Puzzle and obtaining the cipher. Solving it gives the code for the basement door.

## ExplanationEdit

The cipher is a sheet of paper with 12 black dots with the word**PASS**at the top. Under each of the letters in

**PASS**there are 4 black dots. Imagine a line splitting the 4 black dots at the top from the 8 below them (It is easier to insert them into the frame of where the map used to be if you are having trouble imagining a line). Now look at the spaces where the dots are missing at the top. Any missing dots at the highest rows represent the number

**5**, and any missing dots on the lower row represent

**0**. Now look at the missing dots below the line. Any missing dots on the first row below the line represent

**0**. Any missing dots on the second row from the line represent

**1**, and so on. Now add

**P`**s missing dots together,

**A**`s missing dots together,

**S`**s missing dots together, and

**S`**s missing dots together. Line those numbers up in place of

**PASS**to give you the basement door code.