Every geocacher loves a smiley, and now there's six more up for grabs in the Whakarewera forest
Unless you're a very good guesser, in order to find the sixth bonus cache, you'll need to find the first five caches in the series and use the numbers in each to get the co ordinates for the Bonus. You will need to BYOP for this series.
Once you have completed the rest of the series use the numbers collected to communicate with the cache to find out where it is.