三さんカ年ねん

Meanings

noun-modifying (irregular)

triennial; three-year (plan, period, etc.)

Used attributively to describe a plan, project, or period spanning three years. Common in government, business, and institutional contexts.

三さん年ねん
三年 is the general term for 'three years' as a duration, while 三カ年 is more formal and often used in official names of plans or periods.

三さんカ年ねん
Commonly used in official documents and plans; the small katakana カ is a standard way to write the counter.
三ヶ年さんかねん
The small katakana ヶ is a variant of カ and is also widely seen.
三さんか年ねん
Hiragana か is sometimes used, but less common in formal writing.
三さん箇か年ねん
Uses the kanji 箇, which is the formal character for the counter; rarely seen in modern texts.
三ヵ年さんかねん
Variant with small katakana ヵ; less common than カ or ヶ.
三ケ年さんかねん
Full-size katakana ケ is occasionally used but nonstandard.
３さんカ年ねん
Using Arabic numeral 3 instead of kanji 三; common in charts and tables.
３ヶ年さんかねん
Arabic numeral with ヶ variant.
３さんか年ねん
Arabic numeral with hiragana か.
３さん箇か年ねん
Arabic numeral with kanji 箇.
３ヵ年さんかねん
Arabic numeral with ヵ variant.
３ケ年さんかねん
Arabic numeral with full-size ケ.

Compound of 三 (three) + カ (counter for years, derived from 箇) + 年 (year). The counter カ/ヶ/か is a simplification of the kanji 箇.