Here are the basic coverages you'll find in Tecmo Bowl. The colour coding should make it easy to understand.
Remember that in Tecmo Bowl the defense mirrors itself when playing on the other side of the field. The Top Safety (TS) will always be at the top of the screen, etc
Example, against CHI if you call Run 1 (noted by the blue outline, the computer will cover the bottom WR on Pass 2 with the BOLB. If you control the BOLB you will receive no coverage.
Remember that in Tecmo Bowl the defense mirrors itself when playing on the other side of the field. The Top Safety (TS) will always be at the top of the screen, etc.