Before you dash off towards the Nikoli Hurdles let’s familiarize ourselves with the Answer Keys. This is what you need to extract from each puzzle’s solution.
4 squares in the puzzle will be marked with A, B, C and D. Use the given keys to describe the content of the 4 cells. In shading puzzles, B and W denote a shaded and unshaded cell. In loop puzzles, numbers 1-6 show the possible configurations of the loop segment in that cell. Cells in number-filling puzzles can be represented by that particular number itself. For two digit numbers, only use the digit in the ones column.
Using this notation, each answer key should end up being a 4-digit number. (With B and W in some cases).
More details coming soon!