CACHE IS AT THE POSTED COORDS.
The objective of this challenge is to make two lines, as in the example below both horizontally from the 1st to the 31st, and vertically from January to December, with dates / squares containing AT LEAST 10 finds.

When moving horizontally, you CANNOT make a vertical move. For example, if you start on 1st August, you can only 'move' to 2nd July, 2nd August or 2nd September. You CANNOT 'move' to 1st July or 1st September. So, you have to complete your 'move' across the calendar using EXACTLY 31 dates / squares. The implication here, of course, is that you have to have found at least 10 caches on at least one of the 31st of January, March, May, July, August, October or December.
Similarly, when moving vertically, you CANNOT make a horizontal 'move'. For example, if you start on 15th January, you can only 'move' to 14th February, 15th February or 16th February. You CANNOT 'move' to 14th January or 16th January. So, you have to complete your 'move' down the calendar using EXACTLY 12 dates / squares.
You might have at least one square which will be in your horizontal and vertical links, but any like this still only have to contain AT LEAST 10 finds.
You may find this cache prior to qualifying. Just sign the log and write a note on the cache page of your current Double Digit Calendar Challenge status. Then when you qualify you may claim the find on the cache.