1. Strongside Run Defense
The key to run defense is understanding how the run blocking scheme works. On run plays in Tecmo Bowl, 3 defensive players are not blocked! Using these position players you can limit rushing yardage allowed. The positions are: Defensive end (Red arrow), Outside Linebacker(Yellow arrow), Defensive Back(Blue arrow).
On a run play to the bottom half of the field, the Top D-end, Top outside LB, and Top DB are not blocked. On a run play to the top half of the field, the Bottom D-end, Bottom Outside LB, and Bottom DB are not blocked. When your defender gets blocked, the running back can rack up the yards. When your defender is not blocked, its easy to tackle the running back for a short gain.
To shut down the run game, pick the run play directed at your half of the field. For example, choose the top run, and be the top D-end. By doing so, it stops the run play to the top side of the field, which you would be blocked on if you don't call that play. Furthermore, it allows you to stop the RB for a short gain when the offense chooses run play to the other half of the field. It's that easy!
See video on how strong side run works, with additional run defense tactics
2. Bunk Bed Defense
The field in Tecmo Bowl has a top and bottom half, as does a "bunk bed". This ploy involves the defensive back. What you do is choose the top side DB for example and call the bottom run play. This is the opposite of what was discussed above with strong side run, and this ploy only works with the DBs. What happens is the run play furthest away furthest away from the DB is stopped because you called it. The other benefit is that this call short circuits the offensive run blocking scheme and the DB is completely unblocked on the run play to his half of the field. The result is an easy tackle. The added benefit as the distance that your DB has to run to make the tackle. See the illustration showing the difference in distances.