In the Katha Range of central Myanmar, lithologic tracers and pressure-temperature-deformation-time data identify Cambro-Ordovician, Indian-affinity Tethyan Himalaya Series (THS), located ~700 km from their easternmost outcrop in S-Tibet and ~450 km from Himalayan rocks in the Eastern Himalayan Syntaxis (EHS). Metamorphism began at ~65 Ma, peaked at ~45 Ma (~510°C, 0.93 GPa), and exhumation/cooling (~25°C/Myr) occurred until ~30 Ma in a subduction-early collision setting. When the Burma microplate—part of the intra-Tethyan Incertus-arc—accreted to SE-Asia, its eastern boundary, the southern continuation of the Indus-Yarlung suture (IYS), was reactivated as the Sagaing fault (SF), which propagated northward into Indian rocks. In the Katha rocks, this strike-slip stage is marked by ~4°C/Myr exhumation/cooling. Restoring the SF system defines a continental collision-oceanic subduction transition junction, where the IYS bifurcates into the SF at the eastern edge of the Burma microplate and the Jurassic ophiolite-Jadeite belt that includes the Incertus suture.