Blocksperre

Blocksperre (from Ger­man) – a ban on leav­ing the blocks, used in the camps espe­cial­ly when the Nazis need­ed to car­ry out an oper­a­tion with­out wit­ness­es, e.g. to exe­cute a large num­ber of pris­on­ers, to con­duct a selec­tion, etc.