Semi-Final 1
- Episode aired Dec 4, 1972
- 30m
![Mastermind (1972)](https://m.media-amazon.com/images/M/MV5BMzhkYWVjMTctYTU4Zi00MTg4LTk5MzItODc2Mzk3ODFiNzFlXkEyXkFqcGdeQXVyMTUyNjc3NDQ4._V1_QL75_UX190_CR0,2,190,281_.jpg)
The first of the semi-finals, featuring four of the 11 first-round winners.The first of the semi-finals, featuring four of the 11 first-round winners.The first of the semi-finals, featuring four of the 11 first-round winners.