Lithology is an important characteristic of the terrestrial surface, whose properties influence chemical weathering rates. Specifically non-silicate minerals may contribute significantly to the weathering derived fluxes from silicate-dominated lithological classes. The Japanese Archipelago consists of predominantly silicate-dominated lithologies with a high proportion of volcanics. However, the spatially explicit representation of chemical weathering rates remains difficult for such a large region, because many controlling factors on chemical weathering rates are correlated with each other. Due to the spatial heterogeneity of lithology, a multi-lithological model approach to estimate spatially explicit chemical weathering rates for unmonitored areas is applied here. To achieve this, hydrochemical data of 381 catchments are used to train a set of models, recognizing the contribution of a variety of proposed factors influencing chemical silicate rock weathering rates (CSRWR: cations plus dissolved silica flux). The monitored catchments cover ~ 44% of the Japanese Archipelago. Cation chemical weathering rates (excluding Si) are linearly correlated with CSRWR and show outliers if basic volcanics or pyroclastic flows are present due to increased silica release rates.