〈黑土〉(《台湾新聞》1940.11)、〈春秋〉(《台湾時報》1941.4)以及〈曙光〉(《台湾文学》1943.7)可説是坂口農業移民的三部作品。對土地執着的農業移民的姿態、以及懐念「内地」的移民的郷愁,連貫此三部小説。依移民時期之不同,此三部小説對郷愁之著墨亦有差異。〈黑土〉裡故郷来的人與自故郷寄來的土,喚起了難以說出口的郷愁。而決心埋骨於臺灣的移民,將土混合在臺灣的田地上,希望移住地的土變成故郷的土,讓子孫能永遠生存。〈春秋〉不似〈黑土〉般描述郷愁,但藉著主人翁的母親説出精神無所依靠的悲傷,郷愁無法從信仰中得到慰藉。〈曙光〉裡移民對故郷的憧憬與感傷依舊存在。透過主人翁品子與修這兩位外來的闖入者,指出移民村的村民以扭曲的方式,來表達深藏内心的郷愁。而對郷愁的解決之道便是切斷郷愁,落地生根,將異郷當做新的故郷來經營。
In” The Black Earth”, ”The Spring and the Autumn” and ”The Dawn”, Sakaguchi mainly describes the agricultural immigrants' attachment to the earth and their nostalgia to the mother country. According to different immigration periods, t he portrayals on homesickness in these works are various. In ”The Black Earth”, t he people and the earth from their home country arouse the homesickness which had been expressed by the immigrants. Making up their minds to bury the bodies in Taiwan, the immigrants mix up the earth from the home country with that of Taiwan and hope that the earth of Taiwan can turn into the earth of home country in which their descendants can live forever. ”The Spring and The Autumn” is different from The Black Earth in describing nostalgia but indicating that the sadness and the religion can not cure the homesickness through the protagonist's mother. In ”The Dawn”, the immigrants' longing and homesickness toward the home country still exist. Through the two outsiders-Shinako and Osamu, The Dawn depicts how the immigrants in the immigrant community distortedly express their homesickness. The resolution to cure homesickness is cutting off their attachment to their home country and building up their own new home country in distant lands.