"Teki ni shio wo okuru" is a Japanese phrase that is literally translated as "to send salt to your enemy" the meaning of which is taken to be that even in conflict, one should act with humanity.
The origins date back to long running conflicts and feudal disputes that ravaged Japan prior to unification under a single Shogun in the early 17th century. Laying siege to a castle, the lord of the besieging army believed it unfair to starve out his enemy and delivered salt so that he may live to fight (and presumably die) in true battle for the lands.
The question arises though as to whether this is the appropriate colloquial translation. Given that the attacking army was looking to ensure the destruction of the defenders through open battle where they could be despatched through arrow and sword a more accurate translation might be "If a jobs worth doing, it's worth doing well".