noun-modifying (irregular)
nine-year; novennial; recurring every nine years
Used attributively before nouns like 計画 (plan) or 事業 (project) to indicate a span or recurrence of nine years. Formal, often found in official documents and statistics.
This is the final year of the nine-year plan.
This survey was conducted over a period of nine years.
九年 is the simple noun 'nine years', while 九カ年 is a prenominal adjective form used before another noun, often in formal contexts.
Standard kanji-kana mixed spelling for 'nine years' in formal contexts like plans or statistics.
Variant using the small katakana ヵ, common in official documents.
Variant using the small katakana ヶ, often seen in print.
Hiragana variant, less formal but still used.
Kanji 箇 is a formal counter, rarely used in modern writing.
Variant with full-size katakana ケ, less common.
Arabic numeral variant, common in tables and lists.
Arabic numeral with small ヵ.
Arabic numeral with small ヶ.
Arabic numeral with hiragana か.
Arabic numeral with kanji 箇, very formal.
Arabic numeral with full-size katakana ケ.
Compound of 九 (nine) + カ (counter for years, from 箇) + 年 (year). The カ is a simplified form of the counter 箇, commonly used in time spans.