How to Solve Brain Chase 2016: The Mask of Tomoe Gozen

What were the strange circles in the videos? Why was there a paint-by-numbers picture in the background? Where in the world was the Mask of Tomoe Gozen buried?


tomoes mask

There were five types of clues hidden in the Summer 2016 animations: red words, encoded letters, pictures of atoms, hidden images, and, of course, the masks, keys, and other items. Let’s break it down.


Hidden Masks, Keys, and Other Items

Each episode contained three hidden objects that related keyto the overall story: a mask, a key, and something tied to that week’s bonus challenge (decoder rings, MP3 plyers, UV lights, tracking devices, and protractors). These images related symbolically to the treasure hunt, but neither the objects themselves nor their placement in the animations contained any clues to the location of the buried treasure. These images were intended to provide motivation, a diversion, and a feeling of accomplishment to some of the program’s younger participants who might otherwise have felt overwhelmed by the more intricate puzzle.



colors 3Red Words

The first episode of each week of Brain Chase began with a quote by a famous scientist, and certain letters of each quote were highlighted in red. As the other letters disappeared, the red letters remained, with each set of letters spelling a word that would prove a vital hint to solving the treasure hunt: science, pigpen, atoms, stir, and colors. More on these words later…







Encoded Lettersmonarchy

Several of the animated episodes contained letters encoded with a Pigpen Cipher. Participants received custom Brain Chase pigpen decoders in the mail precisely for the purpose of decoding these messages, and the first of the program’s Bonus Challenges involved cracking a Pigpen code just for practice. When found and deciphered, the pigpen clusters revealed a riddle, as well as a few other clues.





The words and letters Monarchy, CI, FE, FH, G0, and Red cabbage water emerged as the season went on. “Monarchy” was one of the first significant clues – it indicated that the country concealing the mask is governed by a monarchy, which narrows down the global options considerably. More on the other clues in a moment. First, the pigpen riddle:



This riddle indicated the location of the buried treasure, but it was fairly vague. For those familiar with the periodic table of elements, the element Au represents gold, which seems to fit better with the rhyme. This substitution served as a hint that chemistry and the periodic table come into play in finding the treasure.

Those who remember the opening lines of the Gettysburg Address will recall that a “score” represents twenty. So the treasure was 20 x 15, or 300 miles away from a “chemical island” of some sort. But what is a chemical isle, and which direction must we travel? The other pigpen clues offered some help. By using the number grid in video 1B (see below), pigpen codes can also be converted into numbers. Doing so with the four pigpen clusters changed the letters CI, FE, FH, and G0 to 39, 65, 68, and 70. On the periodic table, these numbers represent the elements of Yttrium, Terbium, Erbium, and Ytterbium, respectively. What do these elements all have in common? They were all discovered near the small Swedish village of Ytterby (now we’re not just learning about chemistry – we’re learning the history of chemistry!). Ytterby lies on the Swedish island of Resaro, which has become famous due to the discovery of four new elements on its surface. Resaro is the chemical isle, and the treasure was buried about 300 miles away. To find out exactly where, you’ll need to do a few chemistry experiments.






The mysterious circles hiding in the animations were nothing more than atom illustrations. These atoms, when strung together with others in the same episodes, created the following molecules:

  • H-H-O, or H20, or water
  • N-H-H-H, or NH3, or ammonia
  • Na-O-H, or NaOH, or lye
  • Na-H-C-O-O-O, or NaHCO3, or baking soda
  • C-H-H-H-C-O-O-H, or CH3COOH, or vinegar



The purpose of these compounds becomes clear when you combine the red letters Stir and Colors with the encoded clue “red cabbage water.” That’s right, solving the riddle means performing your own hands-on chemistry experiment (or watching the experiment online). It turns out that red cabbage water is a good Ph indicator for different compounds, and when you add cabbage water to different ingredients and stir, chemical reactions occur that change the colors of the substances. Here’s what happens:

Water stays purple, but ammonia turns green, lye turns yellow, baking soda turns blue, and vinegar turns red. More on the significance of these colors shortly…


ph indicator




Other Hidden Pictures

crownA few other hidden images were sprinkled throughout the series. These included images of crowns, the calendar/number grid mentioned above, images of red cabbage heads, and a two-part paint-by-numbers picture.

The crowns corresponded with the pigpen clue “monarchy” as a hint that the mask is buried in a nation governed by a king and queen. The calendar/number grid served to translate pigpen clues into numbers, and the heads of cabbage reinforced the final pigpen clue, “red cabbage water” (see above).





pbn2b pbn1


The two paint-by-numbers posters were essential to understanding the colors derived from the cabbage experiments. The first time we saw the image, it was a poster hanging in Akira’s bedroom and called little attention to itself. But when the poster reappeared outside of Osaka Castle – this time in black and white and filled with pigpen numbers, the pair became significant. Deciphering the pigpen numbers with the help of the number grid in 1b, then comparing the location of the number with the color on the first poster yields the following key:

  • green = 19
  • purple = 33
  • yellow = 68
  • red = 8
  • brown = 15
  • blue = 7
  • gray = 6







Putting It All Together

Combining the colors derived from the cabbage experiment (purple, green, yellow, blue, red) with the paint-by-numbers key reveals this number sequence: 33, 19, 68, 7, 8. Going back to the periodic table, these numbers correspond to the following elements:

Arsenic (As), Potassium (K), Erbium (Er), Nitrogen (N), and Oxygen (O). The abbreviated elements As K Er N O spell Asker, NO, indicating the village of Asker in Norway – a town approximately 300 miles from the Swedish island of Resaro, in a nation that’s ruled by a monarchy. The treasure is buried in a forest in Asker, so clicking the map on the city center places you within a two-mile radius of the prize.






Just for Fun

Because some mail never reaches its destination, we seldom include critical clues in the letters. But we also can’t resist hiding a few things in the text. Here’s what we did:

Letter #1 – The Decoder Ring. You may have noticed several typos in this letter, specifically, several letters missing from the text. Using the pigpen cipher to decode the message at the bottom of the page revealed the words “mind the omissions.” Going back through the letter and correcting the typos (by adding missing letters) gives you the letters u-n-d-e-r –a–f-o-r-e-s-t. The treasure was truly buried under a forest in Norway, but this clue is non-essential for locating the prize.

Letter #2 – The UV Pen & Zinc Sulfide. This letter contained some legalese at the bottom relating to the zinc sulfide powder. It also contained a pigpen code at the bottom, which, when deciphered, read “little letters make a Cardan Grille.” To create a Cardan Grille, you need some “windows.” In this case, the clue indicates some significance around the little letters. Several letters in the legalese were intentionally left lower-case. Poking a small hole in these letters creates the Cardan Grille. Then, if the lower portion of the letter is folded exactly over the text above, making a small pencil mark through each hole touches the letters e-l-e-m-e-n-t-a-r-y. This was a difficult puzzle to solve, so it has little bearing on the overall treasure hunt, except to insinuate a connection with the elements, or the science of chemistry. I know it was tricky, but we couldn’t resist.

Letter #3 – The Clinometer. The bottom of this letter contained a series of coordinates: first degrees, then inches. You’ll also notice that the letter contained a small + sign in the lower left-hand corner. Using the newly unwrapped protractor and framing its base on the +, this puzzle can be solved by marking the letter at each coordinate (degrees and inches from the +), revealing the letters b-u-r-i-e-d. Again, not a critical clue, but a fun “Easter egg” nonetheless.



Did you recognize any faces in this year’s animations? An early episode reveals Sean teaching Jack and Grayson Engler some rappelling skills. The Englers were the winners of the first-ever Brain Chase program in 2014. And what about the crew that saves the day in episode 5b? Ashton Detwiler was the first to locate the Sunstone of Cortes near Mt. Fuji in 2015. And, the two dudes in the castle talking about ghosts? They’re none other than Chris Wyatt and Shane Minshew, the screenwriter and producer of the Brain Chase series.





What do you think? Were you able to solve the mystery? Did you find other clues we didn’t mention here? Let us know by emailing

There’s more adventure where this came from. Register today for the next Brain Chase program, and you could be the next treasure hunter traveling around the world to claim your prize. 


Good luck!


Dad and Co-founder

Team Brain Chase