In this view of the Shakujii River as it passes through the Oji district, the patches of orange reflect the famous autumnal display of maple trees in the area. The Takinogawa of the title, meaning "Waterfall River," is an appropriate name for the river at this point, which was known for its Seven Falls (encountered earlier in number 49).
Unfortunately, the glorious orange color of the maples has blackened with age, spoiling the intended effect. The pigment used here is probably either red lead or iron oxide, both of which can blacken over time with exposure to air.