r three cells.  When those cells lie within the same row and region, they can be used for elimination during cross-hatching and counting. Puzzles solved by scanning alone without requiring the detection of contingencies are classified as "easy"; more difficult puzzles are not readily solved by basic scanning alone.    A method for marking likely numerals in a single cell with dots. To reduce marking, this would wait until as many numbers as possible have been added via scanning. Dots are erased as the numerals are eliminated as candidates.ගොනුව:Sudoko-Row contingency.svgThe bottom middle sub-square needs a 3, 5, and 6 in the top row.  This creates a contingency which, although unresolved, reveals that the green square must be a 4.Marking up[සංස්කරණය]Scanning stops when no further numerals can be discovered, making it necessary to engage in logical analysis. One method to guide the analysis is to mark candidate numerals in the blank cells.Subscript notation[සංස්කරණය]In subscript