50 Pence

Ireland's 50 pence was one of the last pre-decimal survivors in Western Europe — the heptagonal format was retained through decimalization in 1971 precisely because the distinctive shape allowed blind and low-vision users to identify it by touch without relying on size alone. The same logic had driven the original 1969 introduction of the seven-sided design, borrowed from the recently issued British 50p, with both countries briefly sharing a currency peg that made dimensional compatibility a practical concern.

The series ran across three decades with minimal modification, making date runs a more accessible collecting goal than most Irish decimals.