Instead of offering the Imperator (1st Series) in the USA, Richter chose to make a different series of sets which were called Anchor Blocks. The sets contained metal parts, as can be seen in the picture below. Only A-B # 5 is exactly identical to its European counterpart Im # 6. The A-B series was more intelligently integrated into the line Anchor sets. A-B # 5 is equal to set GK-NF # 4 plus GK-Br # 4; A-B # 7 is identical to GK-NF # 6 plus GK-Br # 6. In like manner A-B # 11 is related to the two # 8 sets. (Don't ask about A-B # 9). Because of this relationship, new designs, whether based on American themes or not, were not needed or made.