A conservative method of assessing a hand’s playing strength, typically used in assessing whether the hand qualifies for a strong opening bid. In your long suits, you assume partner is void and the second most favourable distributional division of the other cards. In the other suits, you assume no help from partner (typically three low cards).
Hand 1 has eight clear-cut tricks. Even facing a void, the spade suit will play for no loser if the break is either 3-3 or 4-2.
Hand 2 has only six clear-cut tricks. Facing a void, the spade suit will play for one loser on a 5-2 break, the second most favourable. The ♥Q, being of uncertain value, does not count towards the total of clear-cut tricks. This term is no longer in regular use.