Kanji are not syntactic heads. They do not Merge, Agree, assign Case, or host Voice/Appl. When we study classifiers or VN-suru, we study functional morphology / lexicon that happens to be written with kanji. Orthography ≠ syntax.

Honda’s unified model

Honda (2019) surveys morphographic vs morphophonic theories and proposes a compact model:

This covers both transparent compounds and opaque / phonographically assigned items without treating graphs as pure ideas.

A mixed writing system

ScriptTypical job
KanjiContent words / stems (SJ, native, hybrids)
HiraganaParticles, inflection (okurigana), many function words
KatakanaLoans, onomatopoeia, emphasis, scientific names
RōmajiLatin script for acronyms, design, some pedagogy

Kanji are a major subpart of the signary, not the whole writing system.

Joyce’s morphographic principle

Orthographic units primarily represent morphemes and are arranged to match morphological structure. For two-kanji compounds, Joyce (via Nomura, cited in Honda) lists formation patterns that are mostly morphologically motivated:

PatternExampleGloss
Modifier + modified国道こくどうcountry + road → national road
verb + complement登山とざんclimb + mountain → mountain climbing
complement + verb外食がいしょくoutside + eat → eat out
associative pairs親子おやこparent + child
synonymous pairs変化へんかchange + change → change
derivation不明ふめいun- + clear
phonetic borrowing葡萄ぶどうgrapes (ateji / exception)

On / kun dual strata

The same graph packages different lexical strata and phonological shapes. Clinical and psycholinguistic work (cited in Honda) supports dissociable pathways — but readings are spell-out routes, not argument slots.

Graph 人 人じん / にん (on) · 人ひと (kun) · as classifier 三人さんにん Same graph, different strata — not different arities.

Scalar compositionality

Semantic transparency of compounds is greater-or-lesser, not either-or (Honda citing Körtvélyessy et al.):

More compositionalMore opaque / bleached
国道こくどう ‘national road’勉強べんきょう ‘study’ (hist. strive + strength)
登山とざん ‘mountain climbing’挨拶あいさつ ‘greeting’ (compositionality lost)
変化へんか ‘change’葡萄ぶどう ‘grape’ (phonetic borrowing)

See worked examples · compounds for the fossil zone and non-claims.

Okurigana — inflection lives in kana

Inflectional verbal morphology is largely spelled in kana after a kanji stem. The productive morphosyntax of tense, aspect, and politeness sits outside the kanji graph — further evidence that graphs are not Infl heads.

Stem + okurigana 食たべる · 食たべた · 食たべます Kanji stem 食; inflectional endings in hiragana.

Ideography critique (sidebar)

DeFrancis–Unger Critique + Lurie (2006) historiography: characters track speech units (syllables / morphemes), not disembodied concepts. Honda: despite persisting popular belief, kanji are closely related to phonological, morphological, and semantic properties of the Japanese lexicon. Project rule — do not treat kanji as idea-writing that bypasses syntax.

Sources. Honda 2019 (open PDF); Joyce 2011 DOI 10.1075/wll.14.1.04joy; Lurie 2006. Full map on Sources.