Vocabulary Tier System

This dictionary uses a three-tier vocabulary classification system instead of JLPT levels. This approach provides a pedagogically coherent organization based on actual learner needs rather than test-preparation categories.

Overview of the Three Tiers

Basic Tier (600-800 words)

The most fundamental vocabulary that forms the foundation for any person learning Japanese, regardless of purpose.

Characteristics:

• Words needed from the very first days of study
• High-frequency function words (particles, pronouns, basic conjunctions)
• Essential verbs for daily actions (to be, to go, to eat, to see, etc.)
• Core adjectives for basic description (big, small, good, bad, etc.)
• Numbers, time expressions, and basic counters
• Fundamental nouns (person, thing, place, time, etc.)
• Basic question words (what, who, where, when, why, how)

Target learner: Complete beginner through early intermediate. Someone who has studied for approximately 3-6 months should know most basic tier vocabulary.

Core Tier (1600-2000 words)

Vocabulary expected to be known by any adult using Japanese for work, study, or social life.

Characteristics:

• Words needed for general adult communication
• Common verbs for workplace and social contexts
• Adjectives for nuanced description
• Nouns for everyday life, common objects, and general concepts
• Standard counters beyond the most basic ones
• Conjunctions and transition words for coherent speech/writing
• Words for expressing opinions, emotions, and abstract ideas

Target learner: Intermediate learner through advanced. Someone actively using Japanese in professional or social contexts should know most core tier vocabulary.

General Tier (no word limit)

All vocabulary not classified as basic or core.

Characteristics:

• Specialized or technical vocabulary
• Less frequent words
• Literary or archaic expressions
• Domain-specific terminology
• Regional or dialectal words
• Formal/keigo vocabulary beyond common patterns
• Words for specialized topics (science, law, medicine, etc.)

Target learner: Advanced learners, specialists, or those with specific domain interests.

The Self-Containment Principle

CRITICAL: Both basic and core tiers must be as self-contained as possible for semantically and functionally similar terms.

What This Means

If members of a natural semantic or functional group are included in a tier, all members of that group should be in the same tier. This prevents fragmented learning and ensures pedagogical coherence.

Examples of Self-Containment

Numerals 1-10

If {一|いち} is in basic, then ALL of these must be in basic:

• {一|いち}, {二|に}, {三|さん}, {四|し/よん}, {五|ご}, {六|ろく}, {七|しち/なな}, {八|はち}, {九|く/きゅう}, {十|じゅう}

You cannot have {一|いち} through {七|なな} in basic and {八|はち} through {十|じゅう} in core.

Days of the Week

If {月曜日|げつようび} is in a tier, all seven days must be in that same tier:

• {月曜日|げつようび}, {火曜日|かようび}, {水曜日|すいようび}, {木曜日|もくようび}, {金曜日|きんようび}, {土曜日|どようび}, {日曜日|にちようび}

Basic Color Terms

The core color terms should stay together:

• {赤|あか}, {青|あお}, {黄色|きいろ}, {白|しろ}, {黒|くろ}

If these are in basic, extended colors like {紫|むらさき}, {灰色|はいいろ}, {茶色|ちゃいろ} might reasonably be in core.

Family Terms

Basic family terms should stay together:

• {父|ちち}/{お父さん|おとうさん}, {母|はは}/{お母さん|おかあさん}, {兄|あに}/{お兄さん|おにいさん}, {姉|あね}/{お姉さん|おねえさん}, {弟|おとうと}, {妹|いもうと}

Question Words

Basic question words form a natural set:

• {何|なに/なん}, {誰|だれ}, {どこ}, {いつ}, {なぜ}/{どうして}, {どう}, {どれ}, {どの}, {どちら}

The Exclusion Corollary

If a semantic group cannot fit entirely within a tier's word limit, move the entire group to a lower-priority tier.

Example: The 十二支 (Chinese Zodiac)

If you are drafting the core vocabulary and approaching the 2000-word limit:

• You have included {子|ね} (rat), {丑|うし} (ox), {寅|とら} (tiger) in core
• But adding all 12 zodiac animals would exceed the limit
• Solution: Remove all three and place all 十二支 in general tier

This maintains the integrity of the semantic grouping. A learner in the core tier either knows all 12 zodiac animals or none—there's no awkward partial knowledge.

Example: Specialized Counter Sets

Counters for small animals ({匹|ひき}), flat objects ({枚|まい}), and long thin objects ({本|ほん}) might be core.

But if you're near the limit and have only included 3 of 6 floor-counting counters ({階|かい}):

• Either include all floor-related counters in core
• Or move them all to general

Semantic Groups Reference

When assigning tiers, consider these natural groupings:

Groups That Should Stay Together

Time expressions:

• Days of week (7 items)
• Months of year (12 items)
• Hours ({一時|いちじ} through {十二時|じゅうにじ})
• Time periods ({朝|あさ}, {昼|ひる}, {夕方|ゆうがた}, {夜|よる}, {夜中|よなか})
• Relative time ({今日|きょう}, {明日|あした}, {昨日|きのう}, {今週|こんしゅう}, etc.)

Numbers:

• Cardinal 1-10 (10 items)
• Cardinal 11-100 by tens (9 additional items)
• Ordinal numbers ({一番|いちばん}, {二番|にばん}, etc.)

Basic counters:

• Generic ({つ} series: {一|ひと}つ through {十|とお})
• People ({人|にん}: {一人|ひとり}, {二人|ふたり}, {三人|さんにん}...)
• Small items ({個|こ})
• Long thin objects ({本|ほん})
• Flat objects ({枚|まい})

Direction/location:

• Basic directions ({上|うえ}, {下|した}, {右|みぎ}, {左|ひだり}, {前|まえ}, {後ろ|うしろ}, {中|なか}, {外|そと})
• Cardinal directions ({北|きた}, {南|みなみ}, {東|ひがし}, {西|にし})

Body parts:

• Core set ({頭|あたま}, {顔|かお}, {目|め}, {耳|みみ}, {口|くち}, {鼻|はな}, {手|て}, {足|あし}, {体|からだ})

Family:

• Nuclear family terms (as listed above)
• Extended family ({祖父|そふ}, {祖母|そぼ}, etc.) may be separate group

Basic verbs:

• Existence ({いる}, {ある})
• Movement ({行く|いく}, {来る|くる}, {帰る|かえる}, {歩く|あるく}, {走る|はしる})
• Daily actions ({食べる|たべる}, {飲む|のむ}, {寝る|ねる}, {起きる|おきる})
• Communication ({言う|いう}, {話す|はなす}, {聞く|きく}, {読む|よむ}, {書く|かく})

Pronouns:

• First person ({私|わたし}, {僕|ぼく}, etc.)
• Second person ({あなた}, {君|きみ}, etc.)
• Third person ({彼|かれ}, {彼女|かのじょ}, etc.)
• Demonstratives (こ/そ/あ/ど series)

Groups That May Span Tiers

Some semantic groups naturally span tiers based on frequency:

Seasons: {春|はる}, {夏|なつ}, {秋|あき}, {冬|ふゆ} → likely basic or core (keep together) But season-specific vocabulary (e.g., {紅葉|こうよう}, {梅雨|つゆ}) → may be general

Animals: Common animals ({犬|いぬ}, {猫|ねこ}, {鳥|とり}) → basic/core Less common ({熊|くま}, {狼|おおかみ}, {鯨|くじら}) → general

Occupations: Very common ({先生|せんせい}, {医者|いしゃ}, {学生|がくせい}) → basic/core Specialized ({弁護士|べんごし}, {会計士|かいけいし}) → core/general

Decision Criteria for Tier Assignment

Assign to BASIC if the word:

1. Is needed in the first weeks/months of study
2. Appears in virtually all beginner textbooks
3. Is required for basic survival communication
4. Is a core grammatical function word (particles, basic conjunctions)
5. Is a high-frequency verb/adjective/noun used daily
6. Belongs to a fundamental semantic set that should be learned as a unit

Assign to CORE if the word:

1. Is needed for general adult communication
2. Would be known by any educated Japanese speaker
3. Appears regularly in newspapers, general media
4. Is used in typical workplace or social situations
5. Is an expansion of basic vocabulary (more specific verbs, more nuanced adjectives)
6. Belongs to a semantic set appropriate for intermediate learners

Assign to GENERAL if the word:

1. Is specialized, technical, or domain-specific
2. Is low-frequency in everyday communication
3. Is primarily written/literary language
4. Is a term that even native speakers might not know without specific exposure
5. Is an advanced or formal alternative to common words
6. Cannot fit with its semantic group in the core tier due to space limits

Implementation Notes

Tier Realignment Complete (January 2026)

The vocabulary tier realignment project has been completed. The tiers are now fixed at:

• Basic: 795 entries (within 600-800 target)
• Core: 1,998 entries (within 1,600-2,000 target)
• General: 4,566+ entries (no limit)

All entries have been assigned a tier, and semantic groups are kept intact (no groups split across tiers).

For New Entries (IMPORTANT)

All new entries must be assigned to the "general" tier.

Do NOT assign new entries to basic or core tiers. The basic and core tiers have been curated to:

• Meet specific word count targets
• Maintain semantic group integrity
• Cover foundational and adult-communication vocabulary

When creating a new entry, always set:

"metadata": {
  "vocabulary_tier": "general",
  ...
}

The only exception is if explicitly instructed by the user to adjust tier assignments.

For Existing Entries

The basic and core tiers are considered stable. If you need to revise an existing entry:

• Do NOT change its vocabulary_tier unless explicitly instructed
• Basic and core entries were carefully curated to maintain semantic group integrity

Schema Note

Vocabulary tier is stored in the metadata.vocabulary_tier field. Valid values are "basic", "core", or "general".

Examples of Tier Assignment

Example 1: Basic Tier Word

Word: {食べる|たべる} (to eat)

Decision: BASIC

• Needed from very first days of study
• Universal high-frequency action verb
• Part of daily actions verb group (eat, drink, sleep)
• Appears in all beginner textbooks

Example 2: Core Tier Word

Word: {提案|ていあん} (proposal, suggestion)

Decision: CORE

• Common in workplace/adult contexts
• Not survival vocabulary but expected of any working adult
• Used in meetings, discussions, business
• Not specialized—general adult vocabulary

Example 3: General Tier Word

Word: {判例|はんれい} (judicial precedent)

Decision: GENERAL

• Legal terminology
• Most adults wouldn't encounter this regularly
• Domain-specific (law)
• Not expected in general communication

Example 4: Applying Self-Containment

Scenario: Assigning the demonstrative series

The こ/そ/あ/ど demonstrative system:

• これ/それ/あれ/どれ (things)
• この/その/あの/どの (modifiers)
• ここ/そこ/あそこ/どこ (places)
• こちら/そちら/あちら/どちら (direction/polite reference)

Decision: All 16 words → BASIC

Even though こちら/そちら/あちら/どちら are slightly less frequent, the demonstrative system is a coherent grammatical unit. Splitting it would create pedagogical confusion.

Example 5: Applying the Exclusion Corollary

Scenario: Core tier is at 1950 words. Considering adding prefecture names.

Japan has 47 prefectures. Adding even the most famous 5 would:

• Fragment the semantic group
• Leave learners with arbitrary partial knowledge

Decision: All prefecture names → GENERAL

A learner should either know all prefectures or learn them as needed. Partial knowledge of "the 5 most famous prefectures" is not pedagogically useful.

Quality Checklist for New Entries

• vocabulary_tier is set to "general" (required for all new entries)
• Entry follows all other schema requirements

Note: The decision criteria above (basic/core/general) are historical documentation of how the tiers were curated. They should NOT be used to assign new entries to basic or core tiers. All new entries go to general tier.