Parade of the Assassins
Published as one of the backup stories in Operator #5 - #31, February 1937.
"There was no red rose in the vase. So Gregory Grex knew that Yamasina, scourge of the white race, planned to remove him forever from the Yellowese path of conquest."
"A little thing like a missing red rose was Gregory Grex’s only warning that Yamasina, arch-enemy of the white race, was about to remove forever the only barrier to his dream of war-made empire."