(a) Photo of the deeply weathered rocks changing into red soil. The location is the site (a) shown in (a), where the red soil has been exploited for use as an impermeable material for the local farm pond. The sample for the major element analyses was collected from the “+” marked point. Its host rock is observed as the core stone existing at the lower left in this photo. The red and white pole, as a scale, is 2 m in length. (b) Photo of the host rock sample (Cretaceous biotite granite) for the major element analyses collected from the core stone at the lower left in the photo (a). (c) Photo taken in the burdock harvest at the burdock farm in Koresato village (the elevation of ca. 300 m) situated at the northern part of Akaiwa city located in the Eastern part of Okayama Prefecture. The yellow colored farm behind the burdock farm lies fallow. (d) Photo taken before planting burdock seeds at the burdock farm in Meiji-Gonbo village (The official name is Yoshii, where the elevation is ca. 400 m), which is situated at the northern part of Ibara city located in the western part of Okayama Prefecture.