An in-browser spinning top built around a sliding contact point that moves across the body as the top tilts. A tippe top inverts and stands on its stem, raising its own centre of mass; a peg top rises, sleeps and wakes; and two 20.000 mm tops fight a Koma Taisen bout in a 250 mm concave dohyo under the association's own published rules. Hand-written rigid-body engine and WebGL2 renderer, no libraries, no model, no network. Jellett's integral is conserved to 1e-16 while the energy falls, and removing friction makes the inversion vanish.

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