封 - seal, closing

to seal (e.g. a letter)

sealed letter

seal

sealed move; next move written down and kept sealed in an envelope until the game is resumed the following day

envelope

blockade; lockdown; sealing off (an area)

feudal; feudalistic

total blockage; complete shutdown; stopping completely

economic blockade; embargo

enclosing (e.g. with a letter)

opening (a letter, parcel, etc.); breaking the seal

feudalism