Complex sentence: From his preschool years Toguchi, conincidentally along with the future Gōeidō was enrolled at a local sumo dōjo and in 1996 as a primary school fourth grader, he came in runner up at a national children's sumo tournament.
Split into simpler sentences: From his preschool years Toguchi, was enrolled at a local sumo dōjo, coincidentally the future Gōeidō was also enrolled there at this time. In 1996 as a primary school fourth grader, he came in runner up at a national children's sumo tournament.