As the study of tactics is recommended especially to young and improving chess players, some puzzle books group their exercises not only by theme, but also grade them by difficulty; and some include introductory bits of text that steer the reader in the general direction of the solution. On one hand, purists can protest you’re giving away the answer! while budding Alekhines and Kasparovs will be asking what should I be looking for, what’s important in this position, what do I need – beyond raw calculating power – to solve this thing? For many readers, the “hint” not only makes the difference between a discovery Aha! experience and some otherwise mind-numbing frustration (followed by book-throwing), it teases out and focuses on important factors in the position – a teaching tool in itself.