Buzzfeed Japan: can a (former) high school baseball player tell which dirt sample is from Koshien?

Buzzfeed Japan bought some Koshien dirt from Mercari, Japan’s first unicorn. Can you tell which dirt sample is from Koshien?

Also, why is dirt from the Koshien stadium so treasured? Makoto Kosaka explains in The Japan Times, “The dark side of the Koshien dream“:

How to explain Koshien’s massive popularity? In short, these boys of summer represent the best qualities found in Japanese sports: a self-disciplined work ethic, teamwork, resilience — qualities valued not only in sports but in life. Players who carry home Koshien’s sacred dirt, a memento for any athlete who makes it to the field, are valued in Japan by future employers and idealized by viewers.