I Built Another Japanese Vocabulary Puzzle Game — Kotoba Puzzle

After finishing Kotoba, I started thinking about a new question.

A simple vocabulary memorization tool is very useful for efficient learning, but if every day is only about repeating, memorizing, and reviewing, it can become tiring over time.

So, besides Kotoba, I wanted to build a slightly more game-like Japanese learning app.

That is how I started building Kotoba Puzzle.

Why I Built This Project

Kotoba is designed to be simple, efficient, and focused.

But sometimes I just want to open a small game, play for a few minutes, and review some words at the same time.

So I started looking at two types of games:

• Crossword puzzles
• Match/gem-style games

Crossword puzzles are naturally suitable for language learning because they are closely related to words, spelling, and clues.

Gem-style games provide a lighter and more immediate feedback experience, such as lives, hints, level progression, and small goals.

I wanted to combine these two experiences into a lightweight game suitable for learning Japanese vocabulary.

Core Idea

Normal crossword puzzles are actually quite difficult.

If the game only gives one clue and asks the player to fill in the full word directly, it is very easy for Japanese learners to get stuck.

Japanese vocabulary also involves several layers:

• Kana
• Kanji
• Pronunciation
• Meaning
• Word familiarity

If the difficulty is too high, the game quickly changes from “practice” into “frustration.”

So the design direction of Kotoba Puzzle is not to build a hardcore crossword game, but a version that is more suitable for learners.

In the game, players can see:

• The word meaning
• Pronunciation hints
• The puzzle grid structure

This keeps the thinking process of a crossword puzzle, while preventing the difficulty from becoming too high too quickly.

Support Mechanisms

To make the game experience more balanced, I added several support mechanisms.

For example:

• Lives
• Hints
• Mistake tolerance
• Step-by-step level completion

The purpose of these features is not to make the game complicated, but to reduce frustration during learning.

If I completely forget a word, I can use a hint and continue.

If I make a mistake, the game does not end immediately.

I want it to feel more like a lightweight practice field, rather than an exam.

Current Features

Kotoba Puzzle currently has the basic gameplay implemented.

Two Game Modes

To balance learning and gameplay, I added two modes to Kotoba Puzzle:

• Study Mode
• Free Mode

Study Mode

Study Mode is closer to “learning while playing.”

The system guides the player through words one by one. Players can first check the word meaning and pronunciation hint, then connect the corresponding hiragana on the board.

This mode is more beginner-friendly.

For example:

• The current word is clearly marked
• Players can switch target words from the word list
• The first kana of each word is shown as a starting hint
• After staying idle for a while, a small hint guides the next step

So the focus of Study Mode is not difficulty, but helping me gradually become familiar with the words.

It is more suitable when first encountering a topic-based word list, or when I want to review words with lower pressure.

Free Mode

Free Mode is closer to a traditional word search or crossword-style game.

Players do not need to complete words in a fixed order. Instead, they can freely search for words on the board.

This mode is more challenging because the player needs to judge which kana can form the target words.

On medium and hard difficulty, some unsolved words are hidden, leaving only the meaning as a clue.

If the player taps the wrong tile, that tile is marked and can no longer be used.

This gives Free Mode a stronger game feeling, and makes it more suitable for testing whether I really remember the words after becoming familiar with them.

Why Two Modes

At first, I only wanted to build a simple crossword-style game.

But after actually playing it, I realized that if the difficulty is too low, it lacks gameplay; if the difficulty is too high, it quickly becomes frustrating.

So in the end, I split it into two modes.

Study Mode lowers the entry barrier.

Free Mode adds challenge.

This way, the same word list can be used in two different ways:

First use Study Mode to become familiar with the words, then use Free Mode to test memory.

This also fits my own rhythm of learning Japanese better.

Japanese Vocabulary Puzzle

The game generates a puzzle grid based on vocabulary words.

Players need to complete the words based on the clues.

Compared with simply looking at flashcards, this feels more active because I need to recall and input the answer myself.

Meaning and Pronunciation Hints

Each word provides meaning and pronunciation-related hints.

This is one of the biggest differences from a normal crossword puzzle.

I do not want the player to be purely guessing. Instead, I want the player to gradually recall the word through available clues.

Lives System

Players have a certain number of lives in the game.

Wrong inputs consume lives.

This gives the game a little tension, without making it too serious.

Hint System

When encountering an unfamiliar word, players can use hints to continue.

For a learning app, I think “keep going” is more important than “fail immediately.”

PWA Support

Like Kotoba, Kotoba Puzzle also supports PWA（Progressive Web App）.

If you use it often, you can install it directly on your phone or desktop.

This makes the experience closer to a normal app and more suitable for short learning sessions.

Technical Implementation

The tech stack basically follows Kotoba:

• Next.js
• TypeScript
• Tailwind CSS
• PWA

The project is still Web-first.

I want it to stay lightweight enough that you can open the website and start playing directly, without any complicated setup.

Design Process

The design process mainly used:

• Claude
• ChatGPT

I used Claude for a lot of visual and interface exploration.

For example, the overall style, game screen layout, button states, hint area, level feedback, and so on.

ChatGPT was more involved in product structure, copywriting, interaction logic, and some detail discussions.

Small projects like this are very suitable for prototyping together with AI.

Very often, I first describe a vague idea, let AI provide several directions, then choose the one closest to my feeling and continue iterating.

Development Process

For development, this project used about two weeks of Claude quota.

Later, I also used Codex to help with a lot of development work.

Including:

• Code structure adjustments
• Component implementation
• State logic
• Detail fixes
• PWA configuration
• Overall experience polishing

This process felt more like building a small game than building Kotoba.

Because besides data display, I also needed to think about game rhythm, failure feedback, hint consumption, and whether users would want to keep playing.

Why It Is Not a Normal Crossword Puzzle

I do not really want to build a traditional crossword.

Traditional crossword puzzles are more about knowledge challenges.

But the goal of Kotoba Puzzle is Japanese learning.

So it needs to be friendlier.

It should not make players completely stuck just because they cannot remember one word.

It is more like:

Reviewing vocabulary through a game.

Rather than:

Making a difficult game out of vocabulary.

This is the distinction I care about most in this project.

Future Plans

Next, I plan to keep improving:

• Level difficulty
• Word selection logic
• Hint system
• Game feedback

If I have more time later, I also hope Kotoba Puzzle can form a more complete learning combination with Kotoba.

Kotoba is responsible for efficient memorization.

Kotoba Puzzle is responsible for lightweight review and game-like practice.

One is more focused.

The other is more relaxed.

Try It

If you are also learning Japanese, feel free to try Kotoba Puzzle.

https://kotoba-puzzle.wangpeifeng.com/

It is not a serious exam tool, but a small Japanese vocabulary game that you can play for a few minutes during spare time.

If you find any bugs, or have suggestions about gameplay, difficulty, vocabulary, or interface design, feel free to let me know.

[email protected]

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Technical Information

• Framework: Next.js
• Language: TypeScript
• Styling: Tailwind CSS
• PWA: Supported
• Design: Claude + ChatGPT
• Development: Claude + Codex

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Keep learning. Keep improving.

Kotoba Puzzle — A lightweight Japanese vocabulary puzzle game.
楽しく、少しずつ。