South Africa 1913 KGV ½d Crack Thru RICA of Africa, Plate Block

1913 KGV ½d green (SG 3var) VF/M/UM upper right corner PLATE NO 7 BLOCK of six showing variety CRACK THROUGH "RICA" of AFRICA to base of crown (UHB V3) which only occurred on Plate 7 stamp row 1/12. Previously hinged top margin and lower stamps, Plate pair is UM. Seldom identified, scarce.