Tokoname Kyusu Teapot (Iron Teapot texture） 香臣藻掛大理石.
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Difference of body color (Black) is difference of degree of smoking process (under reduction firing).
Those teapots are originally red (red clay), and at second firing, they are smoked (change to black)
KS09 was more deeply smoked than KS20 so that the surface of KS09 is more blacked.
They were fired at different time (not in the same kiln). Every firing (smoking), degree of smoking is different.