Guidelines for assigning vocabulary to the three-tier system (basic, core, general). Covers tier criteria, word counts, self-containment principles, and semantic grouping.
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.
Related Skills
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:
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.)
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:
Is needed in the first weeks/months of study
Appears in virtually all beginner textbooks
Is required for basic survival communication
Is a core grammatical function word (particles, basic conjunctions)
Is a high-frequency verb/adjective/noun used daily
Belongs to a fundamental semantic set that should be learned as a unit
Assign to CORE if the word:
Is needed for general adult communication
Would be known by any educated Japanese speaker
Appears regularly in newspapers, general media
Is used in typical workplace or social situations
Is an expansion of basic vocabulary (more specific verbs, more nuanced adjectives)
Belongs to a semantic set appropriate for intermediate learners
Assign to GENERAL if the word:
Is specialized, technical, or domain-specific
Is low-frequency in everyday communication
Is primarily written/literary language
Is a term that even native speakers might not know without specific exposure
Is an advanced or formal alternative to common words
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.