Karl E.Ryavec’s ‘Manchu Empire or China Historical GIS? Re-mapping the China/Inner Asia Frontier in the Qing Period CHGIS’ (Inner Asia 6.2) makes an important criticism of the 1820 layer released in Version 1 of the China Historical Geographic Information System (Bol & Ge 2002). I recognise this and shall outline what is being done about it. It also questions the value of creating an historical GIS for the history of successive regimes in the general area of the People’s Republic of China. I respond to this by discussing the role of GIS in spatially-enabled historiography rather than as a contribution to historical geography. Finally, and most importantly, it points to the larger issue of how we might best conceptualise, and represent, frontiers and transitional zones between regimes and different forms of sociopolitical organisation. I shall suggest some possibilities for creating an historical GIS under these circumstances. I write as an historian of the middle-period (8th–15th century) in the first place, but inevitably my comments reflect what I have learned through my involvement with the CHGIS project, for which I am the principal investigator in terms of grants, and coeditor of the Versions 1–3 of CHGIS with Ge Jianxiong, Director of the Center for Historical Geography at Fudan University.