First possible method

The first method is based on a „looking around“ trick: one have to look that in the columns and rows the numbers occur only once. If one looks for the missing number 3 in an Unterquadrat, one looks at the pertinent rows and the columns related to this Unterquadrat, in order to see whether a 3 is already present. If this is the case, this column or row is already omitted from the possible solutions. With this method field for field can be excluded and one finds also little diligence the correct field.

This post is also available in: German French Italian Spanish