Many geocachers instinctively avoid geocaches with the dreaded "question-mark" icon, which designates mystery or puzzle caches. But those who do may be missing out on an important aspect of geocaching. Studies have confirmed that those who continue to stimulate their brains are less likely to develop Alzheimer's disease and dementia, and geocaching puzzles provide excellent opportunities to exercise the mind in addition to the exercise that geocaching already provides to the body. Solving puzzles is also a wonderful way to keep geocaching when the weather outside is too cold or too wet.
An extremely wide range of geocaching puzzles can be found in the Bay Area, and in Silicon Valley in particular. Some puzzles are more appropriate for beginning puzzle solvers, while others may require graduate-level physics or advanced cryptographic knowledge. Choosing the right puzzles to attack can be a challenge in and of itself. Most of the difficult geocaching puzzles have a difficulty rating of 3.5 or higher, but don't get frustrated if you can't solve a 1.5-star difficulty puzzle. Geocache reviewers typically do not enforce any minimum rating on geocaches, and what one geocacher thinks is easy may presume knowledge that not everybody has been exposed to before. The best strategy is probably to start by looking for lower-rated puzzle caches that provide enough information on the cache page to tell you how you need to go about getting the final coordinates. Sometimes the instructions are explicit, such as for GC2CFNM Basic Sudoku Strategies or GC2NRA8 Yet Another Simple Cipher. In some cases, using an internet search engine will help you find numbers that lead to likely coordinates, such as for GC26ZMC I See de Nine or GCG24J Getting to know yahoo. And sometimes, it may not be obvious what you're supposed to do until you try doing something, as in GC1M1CA Classic Positioning System.
Once you've found a puzzle cache that you can solve, you may find that the same cache owner has other caches that might also be solvable. Sometimes, you will find other puzzles mentioned in the logs of other finders. The Geocachers of the Bay Area provides a forum where you can also find out about puzzles that might fit your interests. And when the weather is good, don't forget to go out and find the cache; so that you can claim your find!
