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Borderline Intellectual Functioning — Korea vs Japan System Comparison

The blind spot of IQ 71-84 — people who qualify for neither disability nor welfare

Borderline Intellectual Functioning (BIF) refers to people with IQ scores between 71-84. An estimated 13.6% of the population (about 1 in 7) falls in this range, but most countries leave them in institutional blind spots.

Why a "Blind Spot"?

  • Doesn't qualify as intellectual disability (IQ ≤70), so disability registration is impossible

  • But struggles with complex instructions, financial management, and relationships

  • Labeled as "lazy students" in school and "incompetent workers" at work

  • Many don't know they have borderline intellectual functioning


Korea's System

In 2022, Korea passed the "Borderline Intellectual Functioning Support Act" (effective 2024) — the world's first legislation specifically defining and supporting BIF.

Key provisions: legal definition, national surveys, education/vocational training programs, and dedicated local government offices.

However, actual support infrastructure remains insufficient.

Japan's System

In Japan, BIF is called "グレーゾーン (grey zone)" or "知的ボーダー (intellectual border)." No nationwide legislation exists.

Japan's Developmental Disability Support Act (2005) covers ADHD, ASD, and learning disabilities but not BIF. Some municipalities provide support at their discretion, but no unified national system exists.

Public awareness surged after Miyaguchi Koji's bestseller "The Boys Who Couldn't Cut a Cake" (ケーキの切れない非行少年たち, 2019), revealing that many juvenile offenders had unrecognized BIF.


Key Comparison

Criteria Korea Japan
Legal basis BIF Support Act (2022) None
Disability registration Not possible (IQ ≤70 only) Not possible
Education support Legislated (effective 2024) Partial (tsūkyū), not special support eligible
Estimated population ~6.8M (13.6%) ~17M (13.6%)

Korea-Japan System Comparison

Criteria Korea Japan
Term 경계선 지능(인) グレーゾーン / 知的ボーダー
Legal basis BIF Support Act (2022) None
Disability registration Not possible (IQ ≤70 only) Not possible
Education Legislated (2024) Partial (tsūkyū only)
Est. population ~6.8M ~17M

Key Differences

1

BIF = IQ 71-84, ~13.6% of population (1 in 7)

2

Korea: 2022 world's first BIF Support Act (effective 2024)

3

Japan: No national law — "grey zone" handled at municipal discretion

4

Both: Below intellectual disability threshold → no registration → welfare blind spot

5

Japan: "Boys Who Couldn't Cut Cake" (2019) — BIF awareness turning point