Depth UCT (dUCT), a second enhancement that we propose, is tailored to the problem of retrosynthesis, and is thus domain-specific. Through analysis of retrosynthetic tree structures, we noticed a clear trend. As shown in Figure , the branching factor at shallow depths is far larger than when deeper in the tree. Given the increase in routes to explore at earlier stages, it could be more efficient to focus on the high performing routes in shallow depths, as it would be computationally expensive to explore all the possible disconnections of a given molecule when the options are abundant.