Main Hall

At the centre, you see the portal which apparently is the only way out of here. But in order to use it, you need the magic keys which are hidden in the [Poisonous Yard](https://sudokupad.app/dosj3f0697), the [Library](https://sudokupad.app/fgwlwhjrlw), the [Laboratory](https://sudokupad.app/t7gxiv6e7u) and the [Aviary](https://sudokupad.app/sp7u9y5nm1).

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Rules:

• Normal 6x6 sudoku rules apply, i.e each row, column, and 2x3 region has to contain the digits from 1 to 6 once each.

• Keys: Each key digit has to appear at least once in one of the four centrals cells touching the Portal. Moreover, each key digit has to appear at least once in an arrow's circle.

• Arrows: Digits on an arrow sum to the digit in the circle from which the arrow emerges.