Annular variation of the triangular Hilbert transform at the symmetric point

We prove the annular r-variation estimate for the triangular Hilbert transform from complex $L^3\times L^3$ to L${}^{3/2}$ for every r > 2. The partitions may depend on the output point and range over all positive scales. The estimate yields the two-endpoint maximal bound and joint almost-everywhere and norm principal values, and resolves the symmetric scalar triangular Hilbert transform problem.