A collection of challenging quizzes for adults [Difficult]
Feeling the urge to tackle a brain-busting puzzle that seems impossible—“No one could solve this!”—might be a uniquely adult kind of curiosity.
But why do puzzles and riddles that hinge on sudden insight make your heart race? It’s because your brain is seeking that moment of activation.
This time, we’ve handpicked challenging problems for adults that test flexible thinking and ideas unconstrained by common sense.
Don’t overthink them—try looking from a slightly different angle.
The “aha!” moment is surely waiting for you.
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Compilation of High-Difficulty Puzzles, Patterns, and Codebreaking Quizzes (1–10)
Mirroring Quiz
This is a quiz where you guess what mirror-reversed letters say.
Starting with hiragana and gradually mixing in katakana and kanji makes it increasingly confusing.
If you make it a team competition and have people who don’t know each other work together, it quickly brings them closer.
A quiz of “Aru-Nashi” for advanced players
It’s a quiz where each item is divided into two categories: “has” and “doesn’t have,” and you think about the commonalities and characteristics of the items.
Try various approaches to find the answer, such as imagining how the items look, converting them to hiragana and examining the letters, or adding different characters.
It’s also important that items with similar images are placed side by side in the list, and this closeness in meaning actually makes it harder to arrive at the idea of looking at the letters.
When solving the puzzle, focus only on the items you’re asked to find the commonality for.
It’s best to think it through without being distracted by the others.
High-Difficulty Puzzle, Patterns, and Cryptanalysis Quiz Collection (11–20)
Odd one out game
This quiz challenges you to find the odd-one-out among rows of identical letters or pictures.
Since there are items that closely resemble the ones displayed, the difficulty is fairly high.
Be careful, as your eyes may get tired if you play for a long time.
It’s also a great brain-training quiz, perfect for when you want to loosen up your thinking.
If you’re creating an odd-one-out quiz using kanji or hiragana, using various colors to make items even harder to spot is recommended.
People of all ages can enjoy it, so give it a try as an icebreaker, too.
Letter rearrangement quiz
It’s a quiz where jumbled characters—hiragana, katakana, kanji, and so on—are presented, and you rearrange them to form the correct word.
It’s often introduced as a type of brain-training quiz and is a format you’ll see on TV quiz shows too.
Naturally, the more characters there are, the harder it gets, but once a particular word comes to mind, it can be hard to see any alternatives.
Staying flexible and considering multiple possibilities is the key to finding the right answer.
It’s a quiz you can tackle carefully on your own, or enjoy in a fast-buzzer style with family and friends.
Caesar Cipher Quiz
This is a quiz that uses the Caesar cipher, which creates a code by shifting letters by a fixed number.
For example, if you shift “WORLD” forward by 3 letters, it becomes “ZRUOG.” Even if a word looks meaningless at first glance, the key point is that you can reveal the original word by shifting back using the same rule.
To decode it, you need careful observation and patience to determine the correct shift amount, but the sense of accomplishment when you grasp the pattern can be addictive.
It’s perfect as brain training for adults, since you can have fun while honing logical thinking.
Once you get used to it, you can also encrypt your favorite words yourself and exchange them with friends, making it a quiz with a wide range of ways to enjoy.
