A gesture of friendship and caring from Iowa to Japan — in the form of a couple dozen breeding hogs and some sacks of feed — has stood the test of time. And, as a group of Iowa farmers found out recently, the aid effort 56 years ago is renowned at the highest levels of U.S. diplomacy in Japan even today.

During a visit to the U.S. Embassy in Tokyo during the Iowa Farm Bureau Federation (IFBF)...