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Puzzle Solving 101: Gimme Some OXYGEN!!!

A cache by salsman Send Message to Owner Message this owner
Hidden : 02/11/2012
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What's the deal with all these new puzzle caches lately? Do you ever wonder what the fuss is about? Do you get frustrated when a new cache is published only to find out it's a puzzle? Do you take one look at a puzzle cache, and put it on your ignore list? Do you want to solve more puzzles, but don't know where to begin?

Well, fear puzzles no longer! This puzzle solving tutorial will be your guide into the mind of a puzzle cacher. Simply heed the advice I've laid out below, and you'll be on the fast track to solving puzzles around town in no time. Granted, I can't give away every trick in the book, but follow this advice and the 1, 2 and 3 star puzzles won't seem so daunting anymore. You'll wonder why you didn't start solving puzzles sooner!

I have to give credit where credit is due. A BIG shout out goes to The Allen Cachers. Your How Do I Solve All These Puzzle Caches? was the inspiration behind this puzzle. I hope I did it proud. To all the local puzzle creators who keep me up at night with the nasty things you create. This cache is for you!

The Coordinate String

The goal with almost any puzzle cache is the same -- find the unknown coordinates. Here is a coordinate string you may see in the Rochester area:

N 44° 02.865 W 092° 25.652

The placement guidelines for a puzzle cache suggest the actual coordinates be no greater than two miles from the published coordinates. This is key. This tells you the coordinates you are looking for will almost always start the same way as the published coordinates do. In the Rochester area north will always start with either '43' or '44'; west will always start with '092'.

There are 15 digits in the coordinate string -- seven in the north half, eight in the west. Use this fact to your advantage. Are you given a list or grouping of 15 items? Chances are each item in the list or group corresponds to one digit in the coordinate string. Are you given 14 items? No problem. Oftentimes, the leading '0' is left off of the western coordinates, and you will not need to solve for it. What if only 10 items are listed? Or six? Puzzle creators are well aware of the proximity guidelines for publishing a puzzle. They assume '44' and '092' are given, and you will only need to solve for the minutes, not the degrees. With six items you may only need to solve for the digits to the right of the decimal point. and GPS units use a default coordinate string in degrees/minutes (DMM) format -- ddd°mm.mmm'. This is just one of many different coordinate formats. Two other common coordinate formats are degrees/minutes/seconds (DMS) format -- ddd°mm'ss.s'' and UTM. Here is a converter to convert between these common formats. Your GPS unit can also convert between these and many other coordinate formats. Consult the owner's manual that came with your device for instructions on how to do this.

Now that you've been given an introduction to the coordinate string. Let's look at some of the different methods and techniques puzzle creators use for hiding or encoding the coordinate string.

Fun With the Cache Page

Invisible Text

The easiest way to hide information in the description of the cache page is to make text invisible. Try highlighting the area below, and see if you can find anything.

Congratulations! You've found your first clue to solving this puzzle. A=4.

The first thing I do when presented with a new puzzle is to search for invisible text. Pressing CTRL-A on your keyboard is a shortcut, and will select the entire cache page highlighting any hidden text.

HTML Comments

Web pages use a simple language format called HTML to display the content of the web page. Anybody can view the "code" behind any web page using their browser. Most web browsers will have a "page source" or "view source" option in their menus. The keyboard shortcut in Firefox to view the page source is CTRL-U.

To organize the content of a web page, designers can insert comments that are only visible from the page source. On the text you enter into the description field looks like this when viewed in the page source.

The description section begins with the text "UserSuppliedContent". In the picture above an example of a comment is shown in green. Comments may or may not be colored green on your browser. However, they will always be enclosed in the angled brackets you see in the picture. Try opening the page source for this cache listing, and see if you can find any helpful comments.

Stylized Text

Another way to hide clues in the cache page is to change the style of the text in the description. Cache owners can bold, italicize, underline, or strike text. They can also change the color, size, or font of the text.

Changes like these are easy to see when viewed as I've just showed you. It's possible to hide style changes that are difficult, if not impossible, to see with the naked eye. Take, for example, text using several different shades of red. You can't discern the difference simply by looking at it. In cases like this you'll need to return to the page source to help with the puzzle. Do you notice anything odd about this paragraph? It's hard to see isn't it? Try looking at the page source again. Find this paragraph. Is it easier to see what I've done now?

Beyond the Description

When a cache owner submits a listing they have control over many different aspects of the page. Any location on the page that can be edited by the cache owner can be used to encode coordinates and/or clues to solving the puzzle. Clues can be embedded in the title (very common), the hint (duh!), a related web page link, a background image, the picture gallery, a bookmark list, and/or the attributes.

Another common technique is to hide clues on the pages of nearby benchmarks or waymarks. Did you know there is a "find nearby benchmarks" link on every cache page? Have you ever followed the link? It's often overlooked.

There are also locations outside the cache page where hints or clues could be embedded. Cache owners can hide clues on their profile page, on a travel bug listing they own, or even on their logs of other owner's caches! As a rule of thumb, the puzzle should be solvable from the information provided on the cache page. The answer doesn't have to be on the cache page, but the information needed to get you towards the solution will be.


Image Gallery

Did you know a cache page can have a picture gallery associated with it? Yep, if pictures have been uploaded to the cache page you'll see a "view gallery" link underneath the "Log your visit" link in the upper right hand corner of the page. Cache owners can and do put pictures on their cache page all the time. However, not every picture uploaded to the page needs to be displayed. In fact it takes a second step by the owner to include the picture in the description after uploading. This makes the gallery another good spot to hide things.

Sometimes the picture(s) you see in the gallery or description are imperative to solving the puzzle. What if you haven't a clue what it is you are looking at? In cases like this you can do a reverse image search. Here is a site that can do a reverse image search. To use this search you'll either need to provide the URL of the picture, or you can upload the picture directly.

Background Photo

The gallery isn't the only place for pictures on a cache page. Cache owners often jazz up their page by adding a background image. Can you see the background image for this page? If not try stretching your browser window until it's visible. Do you see the clue yet? No? Some versions of Firefox have an option to view the background image by simply right clicking on the page, and selecting "View Background Image". Internet Explorer may have a "Save Background As" option. If none of these options work for you there is always the page source. Open the page source and search for the text "body background=". You will see the URL to the background image. You can copy and paste this link into your browser to view the image.

QR Codes

This is called a QR code, and they are becoming very popular on puzzle cache pages. If you have a smart phone there are free apps available to quickly scan these codes and read them.

Don't have a smart phone? No problem! Here is an on-line QR code decoder. You can either give it the URL to the picture, or upload the image directly to the decoder. To upload the image, you'll need to save the image to your computer first. To get the URL of the image, either right click on the picture and select "view image", or drag the picture up to your browser's address bar. Either option will get you the URL to the picture.

This decoder will not only decode QR codes. It will also read standard barcodes as well. Pretty cool isn't it? Want to try creating your own QR code? Here is a QR code generator. Have fun!

EXIF Data and Geotagging

Ok, now what on earth is EXIF data? Have you ever taken a photo with a digital camera? If you have a picture on your computer taken from a digital camera look at the properties of the picture. The easiest way to do this is to right click on the photo, and select "properties". If you poke around a bit you may see data related to the type of camera, camera settings, image details, or even GPS coordinates where the photo was taken! This data is called EXIF. The GPS coordinates (if available) is called a "geotag".

You have the ability, if you wish, to edit the EXIF data on any picture you own. Wouldn't this be a great spot to hide a clue to a puzzle? Of course it is! Try saving the QR Code picture from the previous section to your computer. Don't worry, it's safe. Once downloaded to your computer, right click on it, and select "properties". After finding the EXIF data, start looking for clues.


A very common puzzle technique is to provide you with a list of items, and your objective is to determine the coordinates from that list. As discussed above the number of items in the list whether it be 15, 10, 6, etc. is usually a good indication as to what digits you are searching for. The key to solving a list is to determine what the listed items are, what they have in common, and what it is about the items that will give you the coordinates you seek.

Perhaps you are given a list a books or songs. Are they all by the same author or artist? It's easy to determine what those items all have in common simply by using your favorite search engine. What if you have no idea what the listed items are? Did the cache owner leave you any clues to guide you? Is there a hint? Is the title a clue? Remember, there are many places a hint could be hidden.

When you've determined what exactly the list of items is, your next task is to determine how to get a number for each of the items in the list. A puzzle creator needs to use data that is static. For example, the date a book was published. The data used for a list cannot change otherwise the coordinates could vary from solver to solver. This fact can help you narrow down the possible data to use.

Let's look at an example. Consider this list:

  • Separation of Power
  • The Third Option
  • Executive Power
  • Act of Treason
  • .
  • .
  • .
  • Protect and Defend

For arguments sake assume there are 15 items listed. A Google search will probably tell you what these items are. Let's say it doesn't. Assume the title of the cache is "Rapp it Up". Obviously, "Rapp" is a play on words, and most likely a clue. If you search for this list, and include the key word "Rapp" you will learn these are all Mitch Rapp novels by the author Vince Flynn.

Remember, in Rochester your north coordinate string will always start with either 44 or 43. Where can you get a 44 or 43 from the first two items listed? Checking the order the novels were published, the first title listed was Flynn's 4th novel published. The second title in the list was his 3rd novel published. Chances are this will lead to your answer.

One final word about lists, and that is Wikipedia. Wikipedia is a fine and often great resource for searching. However, what makes Wikipedia what it is, is anybody can edit the data you see at any time. Thus, data can and does change. Keep this in mind when using Wikipedia to solve puzzles or create puzzles of your own.

Codes and Ciphers

A cipher (or code), simply put, is a method for performing encryption or decryption. To encrypt or decrypt a series of well-defined steps is performed. To encrypt is to convert information from plain text into code or cipher. To decrypt is to do the opposite -- convert information from code or cipher into plain text.

Ciphers are a difficult topic cover. Countless books have been written about ciphers. There are people who devote their entire careers to solving them. Obviously, I can't teach you everything there is to know. What I can do is introduce some of the more common ciphers I've seen used for cache puzzles. I'll provide links for decoding these and other ciphers not covered here.


One of the simplest ciphers is an alphanumeric substitution. In this cipher letters are replaced with numbers, and vice-versa. For example:

a=1, b=2, c=3 ... z=26

The puzzle you are solving here uses an alphanumeric code.

Anagrams and Cryptograms

What is an anagram? An anagram is a word or phrase formed by rearranging the letters of another word or phrase. For example, "Old West Action" is an anagram for "Clint Eastwood". A popular place cache owners use anagram clues are in the title of cache pages. Here is a anagram solver for your enjoyment.

What is a cryptogram? A cryptogram is a substitution cipher where one letter is substituted with another letter. Cache owners can make a cryptogram more difficult to solve by removing spaces from the original text. Here is a good cryptogram solver. Try solving this cryptogram.

Rifqn dme. Qpmnsfi ubvf sqz effp kmvpo. R favqbz nsiff.


Another way to encode a text string is to use an alternate font. There are thousands of fonts available -- many are human readable. However, many are not. What should you do if you run across a font you haven't seen before? Most of the time the font you see was not typed into the cache page. It was uploaded as an image. A quick way to learn the font in this situation would be to do a reverse image search. Once you know the font you are dealing with the font may be available on your computer. If not, you can do an on-line search to translate the font. Here's a font for you. Have you ever seen it before? (Psst... there's a clue in the gallery...)


Can you speak Spanish? French? What about Italian or Chinese? What do you do if the puzzle isn't even in English? Google Translate is an on-line translation tool you can use. Here's some Portuguese for you to translate.

A letra eu sou igual a nove.

One drawback of on-line translation tools is they are not perfect. Translation from English and back again doesn't always translate the same way. However, it's usually close enough to understand given the context.

Caesar Cipher

A Caesar cipher is similar to a cryptogram in that each letter in the cipher is replaced with another one. The difference being a cryptogram is a random substitution whereas a Caesar cipher is performed by shifting the alphabet a fixed number of spaces. One of the most commonly used Caesar ciphers is known as ROT13. In this cipher the alphabet is shifted (or rotated) 13 spaces. Where have you seen ROT13 before? uses ROT13 to encode the hint section on every cache page. Here is an on-line ROT13 decoder.

Caesar ciphers are not only limited to ROT13. You can shift the alphabet any number of spaces from 1 to 25 to encode a string. Why only 25? If you shift the alphabet 26 times you are back where you started (i.e. a=a). Here is a ROT decoder that will solve all 25 possible ciphers at once. Try it out.

Tbii alkb! G bnrxip qtl.

Vinegere Cipher

Let's take a Caesar cipher one step further. What if instead of shifting the whole text string 13 spaces (for example), you shift each individual letter of the text string a different number of spaces? This is called a Vinegere Cipher. Let's look at an example. Start with the text "aaaaa". Shift the first "a" once, the second "a" twice, the third "a" three times, etc. This is your result:

aaaaa = bcdef

Ciphers like these are difficult if not impossible to decode unless you know exactly how far each character needs to be shifted. To encode and decode a Venegere cipher you need a keyword. The keyword tells you how far to shift each character in the text. Thus, the same keyword used to encode the text is used to decode it. The trick to solving a Vinegere cipher is to find the keyword.

On a Vinegere cipher puzzle the keyword needs to be given by the cache owner, or the puzzle is unsolvable. They may flat out tell you the key, or it might be more subtly hidden in the description, title, hint, etc. For example, the description may say "satisfaction is key to solving the puzzle", or the title of the puzzle may contain a word in italics. Both of these clues are good indications of a keyword. Here is a Vinegere cipher for you to try.

O sgmiasoc imcvbp ow ropw cmgv qfk vvuer qilklpj! O vg quu.

Here is a Vinegere decoder to use. Do you know the keyword? Where did you look? Look at the title of the cache page. Why might there be a word in all capital letters?

Other Ciphers

Like I said, there are so many ciphers out there it is impossible to cover them all. Some ciphers are so common you may know exactly what to do when you see them. Take for example American Sign Language or Braille. Have you ever seen this cipher before?

- .... .. ...  ... .- -.-- ...  .-..  . --.- ..- .- .-.. ...  ..-. .. ...- .  .. -.  -- --- .-. ... .  -.-. --- -.. . .

Yep, it's Morse code. Other ciphers won't be so obvious. Hopefully, there will be some clues to guide you along the way. My goto website for help solving ciphers is The Geocaching Toolbox. Two other sites I've used in the past are Purple Hell and Rumkin.

Math and Numbers

Think about all of the things around you that use numbers. Every single one of them can be used to create a puzzle. Both your computer keyboard and your telephone can be used to convert numbers into letters or symbols. Need to convert time? What about currency?

Number Bases

If you can count from one to ten you are familiar with the base-10 or decimal number system. Base-10 simply means for each digit there are 10 possible numbers.

There's an old joke that says, "There are 10 kinds of people in this world. Those who understand binary, and those who don't." Binary or base-2 numbers, also known as "all those 1's and 0's", are practically impossible to read unless you are a computer. Fortunately, for us humans there are binary conversion tools to make this stuff readable. Try it out.


Have you ever seen numbers that also included the letters A-F? These are called hexadecimal or base-16 numbers. There are hex converters out there too. Numbers can be written in several different bases: base-4, base-7 and base-12 for example. These are not as common as binary or hex so you will not see them as often. However, there are base-X converters available if needed.


What is ASCII? ASCII (ASS-key) is a coding standard for mapping characters to numbers in computer based systems. Computers don't understand characters, they understand numbers. Every character you can see, and those you cannot see (space, tab, etc.), has a numerical value associated with it. Here is an ascii table showing you the character mappings.

To give you an example, look at the table and find the lower case 'a'. It's in red to make it easier to see. The 'a' maps to the decimal number 97. Here are 10 seemingly innocuous numbers. What happens if you map these numbers to characters using the ascii table?

78 32 101 113 117 97 108 115 32 51

Logic Puzzles


This is called a sudoku puzzle. The objective is to fill the 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid contains all of the digits from 1 to 9.

These have been around for years, but have exploded in popularity within the last decade. For this reason I felt I should include an example. Don't worry, I'm not going to ask you solve it. I believe solving these is quite possibly the most mind-numbingly boring exercise in tedium known to man. Fortunately, there are on-line sudoku solvers to spare you the agony. If you want to see something really cool, download the "Google Goggles" app to your smart phone, and scan that sudoku puzzle.

Better than Sudoku

If you enjoy sudoku as much as I do the good news is there are dozens of logic puzzles out there that are a lot more interesting. Nurikabe and Hitori are two of my personal favorites. If you run across a logic puzzle you haven't seen before check out Conceptis. It's a great resource for learning and solving different types of logic puzzles.

The End

I've saved the most important piece of advice I can give you for the end. Ask the cache owner for help! Owners of puzzle caches want their caches found just as much as owners of traditional caches do. I've never met a puzzle owner who wasn't willing to help out if you get stuck, or give you a nudge in the right direction. Don't feel embarrassed. Even the best puzzle solvers struggle through puzzles from time-to-time. Simply explain the ideas you have and the methods you've tried. You might be surprised what you learn!

Well, there you go. That's it. The end. Hopefully, you were able to learn a little something about the fascinating world of puzzle caches. Maybe I've given you that little spark you need to solve a puzzle you've been struggling with, or dust off a puzzle you've given up on. If this guide has helped you solve any puzzle in any way I'd love to hear about it! Send me a message through my profile.

So how did you do? Did you find everything I laid out for you? Are you missing the answer to the letter O? Go back and solve that Sudoku puzzle, and tell me the only decimal digit you do not see. That's the answer to O. Plug the answers you found into this coordinate string. Use the provided geochecker to verify your results.


You can validate your puzzle solution with certitude.

Additional Hints (No hints available.)