What each type is for
The types differ in what they give you rather than in quality, and matching the type to the moment is more useful than looking for the best one.
Speed and precision trade against each other, which is the whole reason more than one is worth having.
| Type | Gives you | Best for |
|---|---|---|
| Bilingual | An equivalent, fast | Reading, beginners |
| Example-based | Usage in context | Learning a word properly |
| Monolingual | Precision, nuance | Upper-intermediate onward |
| Kanji dictionary | Characters, readings | Lookup by component |
| Collocation | What a word goes with | Production and writing |
The last row is the least used and the most useful for writing. Most learner errors are about which words go together rather than about meanings.
Why equivalents mislead
A bilingual dictionary gives a word in your own language that covers part of the Japanese word's range. That is useful and it is an approximation, and the mismatch is where a large share of learner errors originate.
The usual symptom is a sentence that is grammatically correct and uses a word nobody would use there.
| Japanese | Romaji | Meaning |
|---|---|---|
| 聞く | kiku | To hear, to listen, and to ask |
| 見る | miru | To see, to watch, and to try doing |
| やる | yaru | To do, to give, and more |
| かける | kakeru | Dozens of uses, one entry |
| つく | tsuku | Attach, arrive, turn on, and others |
| とる | toru | Take, remove, book, photograph |
Each of these has a range no single equivalent covers. Examples show the range; a definition does not.
Examples over definitions
For anything you intend to use rather than merely understand, example sentences are worth more than a definition. They show which particles the word takes, what it goes with, and what register it belongs to.
This is particularly true of verbs, where the pattern around the verb is most of the information.
- Look at three examples before deciding you know a word.
- Note the particles the word takes; they are part of the word.
- Note whether examples are formal or casual.
- Prefer examples from real text over invented ones.
- If every example is unlike your intended use, it is probably the wrong word.
When to go monolingual
A Japanese-Japanese dictionary gives precision that no translation can, and it costs time, so the switch is worth making when you can read a definition without a second lookup.
Before that point it is a well-intentioned tax on your reading. After it, it improves both vocabulary and reading at once.
- Try it when definitions are mostly readable at a glance.
- Start with words you already half know rather than new ones.
- Keep a bilingual dictionary alongside; switching is not a commitment.
- Use it for nuance between similar words, which is where it is strongest.
- Do not force it early; it slows reading more than it teaches.
Reading fast versus learning properly
These are different activities and want different tools. While reading, the goal is momentum: the fastest possible lookup, and moving on. While learning a word, the goal is depth: examples, collocations, register.
Trying to do both at once produces slow reading and shallow learning, which is the common default.
- While reading: fastest tool, minimal detail, keep moving.
- Note the word rather than studying it in the moment.
- Afterwards: look up the ones that recurred, properly.
- Add only those to your review system.
- Most looked-up words do not deserve a card.
A workable setup
For most learners two tools cover everything: a fast lookup for reading, and something with examples for studying words afterwards. A kanji lookup by component is worth having for characters you cannot type.
The setup matters less than the separation between reading and studying, which is what keeps reading fast enough to be worth doing.
If your reading is being destroyed by lookups, the problem is usually the workflow rather than the dictionary. Note and continue, then study afterwards.