Compared to the entirety of the datasets from which the ring formations were extracted, we found that ring-forming reactions constitute an upper limit of 4.5 % and 5.8 % of the USPTO and Reaxys datasets, respectively (Table ). The number of ring forming reactions is likely lower than that reported as our crude measure of ring change (number of rings in product -number of rings in reactants) includes a change in the number of rings resulting from protections and deprotections. An even smaller percentage of all the templates extracted from these datasets correspond to ring formations (Table ). Therefore, an all-encompassing classifier that considers all extracted templates to predict which can be applied in any given situation, has the difficult task of differentiating templates that can be applied. We propose a specialized ring formation classifier called 'Ring Breaker', that overcomes the current limitations of predicting ring syntheses. This can be injected as needed into a full retrosynthetic tool to enable access to well documented, as well as previously unreported ring systems.