The game took place over 6 days and included over 100 students at the Defence College. This was a classic double-blind wargame and I ran White Cell. Players sent their orders, I processed them on a map and adjudicated results before sending back updated maps with limited information to each side. The entire game was run using email, forum posts and PowerPoint – no specialised software was required. The rules for Siege Perilous would be considered medium complexity by many hobby wargamers, but with hidden information, so many moving parts and so many players, the actual gameplay was a complex and deeply immersive experience.