 Disparities in wealth spread during this period, following an export boom during World War I and subsequent crop failures in the Tohoku region.A "bento" too often reflected a student's wealth, and many wondered if this had an unfavorable influence on children both physically, from lack of adequate diet, and psychologically, from a clumsily made "bento" or the richness of food.After World War II, the practice of bringing "bentos" to school gradually declined and was replaced by uniform food provided for all students and teachers.