Introduction Expert chess players have been a popular population for research in acquired expertise. The putative cognitive underpinnings of chess-expertise (eg. IQ and memory) have been sought for with mixed results. We suggest that this may be partly due to a lack of detail in the analysis of the game itself. We investigated whether different types of chess positions, known as "tactical" and "strategic", activates different neurocognitive structures. In a tactical position the choice of move determines the game, whereas strategic moves are based on long term considerations and do not imply an immediate determination. We therefore hypothesised that tactical considerations rely more on working memory (WM) brain structures, such as the precuneus , while strategic rely on long term memory (LTM), i.e. hippocampus. Methods 22 chess-players participated, 9 during fMRI scanning in a 3T scanner while performing a binary forced choice task on tactical and strategic chess pos. shown for 8 sec. fMRI data underwent a RFX analysis in SPM5 using chess ranking and accuracy difference as explanatory variables. Results Accuracy (P=0.23) and RT (P=0.69) was matched across conditions. Accuracy and chess ranking correlated significantly (r=0.87, P=0.002), suggesting ecological validity of our design. The neural activity was significantly explained by our model (P<0.05, FDR-corrected) in precuneus and hippocampus. Across subjects tactical pos. yielded a higher response in precuneus, strategic pos. gave a higher response in hippocampus. Higher ranking subjects had greater activity in both regions during the tactical tasks compared to lower ranking, and subjects generally had higher responses in both regions during tasks which they performed worst at. Discussion It does make a difference for studies of chess expertise if a detailed account of the game is considered. Our study shows that tactical chess profiles WM regions whereas strategic chess profiles LTM structures. But we also find that other performance mediating factors interact with this general finding in interesting ways.