Tengu format ruling
Narrow Pass

Card effect (current official text)This card can only be activated when both players have 2 monsters or less on their respective sides of the field. Both players can only Normal Summon up to 2 additional monsters on their sides of the field.
Rulings
- Narrow Pass can only be activated when Player A has 2 or fewer monsters and Player B has 2 or fewer monsters. So if there are 3 monsters in play (2 controlled by A and 1 by B) you can activate Narrow Pass. But if either player controls 3 or more monsters on his side of the field then you cannot activate this card.
- Once Narrow Pass is activate, as long as it remains face-up on the field, Player A can Normal Summon or Set 2 up to 2 additional monsters, and Player B can Normal Summon or Set up to 2 additional monsters. It is helpful to place counters on Narrow Pass to keep track.
- If Narrow Pass is activate, and a player Normal Summons his 2 permitted monsters afterwards, if 1 of those is destroyed then he cannot replace it with another Normal Summon. Each player gets 2 additional Normal Summons or Sets, no matter what happens to those monsters afterwards.
- Narrow Pass does not restrict Special Summons or Flip Summons.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.