In the early spring I was advised to take a drastic step to improve my CV and thereby my chances to land a long-term job: teach a class at the Earth and Planetary Sciences department here at Tokyo Institute of Technology. I balked. While subconsciously I knew that teaching was a duty that I would almost inevitably have to come to accept, I was not yet ready to take that plunge. I was put off by the stories my colleagues in lower-tier professor jobs told me about the exhaustive amount of preparation that was required for lecturing, the long working hours and what little time was left to do research. At the same time, however, I realised that I was presented with an opportunity to ease into teaching that would most certainly not be offered elsewhere. Challenge accepted: I contacted the head of the department and agreed I would teach a one-credit course in the autumn semester consisting of seven lectures of 90 minutes each. The best description of the course was given by a colleague as a 'Greatest Hits of Planetary Science'.

As soon as I had finalised the course programme, fixed the dates of each lecture and signed the official document that sealed my contribution a certain anxiety befell me, for I worried I was in over my head. I immediately contacted a friend who has ample teaching experience and vented my angst. 'Teaching is like running an RPG,' my friend said. 'You will need to do some preparation, perhaps for about half the lecture, but the rest of the time you will need to improvise and explain things.' My spirits were lifted, for if what my friend had said is true then this was going to be much easier than I had anticipated.

I realise that a little background information is in order. An RPG is a Role-Playing Game, a definition of which could be: 'A game in which players assume the roles of characters in a fictional setting. Players take responsibility for acting out these roles within a narrative, either through literal acting or through a process of structured decision-making or character development. Actions taken within many games succeed or fail according to a formal system of rules and guidelines.' Like most institutes ELSI has its own RPG gaming group.

For the past five years I have been involved with various groups of people in a tabletop RPG, which is conducted through discussion. Successes or failures of player's characters at specific tasks are determined verbally or decided by dice rolls. An arranger called the dungeon master (DM), now commonly referred to as game master (GM), decides on the rules and setting to be used while each of the other players plays the role of a single character. The term DM came about from the early Dungeons & Dragons RPG ruleset, where traditionally the players' characters would consist of dungeon-delving heroes that would attempt to vanquish a great evil presence deep within and emerge victorious, famous and rich from the plundered treasure.

The role of the DM is far from straightforward. The DM is the interface between the players and the world their characters reside in. The DM tells the narrative, provides quests and challenges to the players, creates the surroundings, acts out the role of enemies (usually monsters) but also regular townspeople (shopkeepers, farmers, royalty, drunkards, beggars, scholars, you name it) and lots more. Running a game successfully takes time and effort, but is also immensely rewarding and provides a fantastic outlet for one's creativity and inspiration. I have no doubt that DM experience also improves one's social and leadership skills. When joining an adventure as a player it is immensely satisfying if the DM guides you along a challenging and humorous adventure that takes you away from the monotony of everyday life. I would even go so far as to say that gaming is addictive.

Of course things are never as easy as they appear. Every DM knows that players seldom follow the path the DM expects them to tread. This calls for formidable improvisation skills and rapid thinking on one's feet. A carefully planned dungeon, intricately laid-out deadly traps, and bloodthirsty monsters lying in wait to wipe out those poor and unsuspecting souls can go to waste or needs to be put on ice because the players did not take the bait. Instead they opt to go on a shopping spree, investigate a rumour from three months back or follow up on some other information that appeals to their characters. In such a circumstance improvisation is the DM's only option to keep the session going.

I discovered that all of this experience is pertinent to teaching a class. As I walked into the classroom for my first ever lecture there were no butterflies in my stomach. There were more students than I had anticipated, which I took as a positive sign. I began my spiel and I was rolling along until one student raised his hand and demanded some background info on a topic I was discussing. I took to the blackboard and explained things to the best of my knowledge, improvising on the way, working from memory. I had not planned for this, of course, and unfortunately had to rush the last part of my lecture, but afterwards I did learn to pace myself. Subsequent lectures fared much better, but my friend was right: roughly half of the time I was providing background info and explanations. Fortunately this is Asia and the students seldom ask questions (or respond to mine). One thing is certain: DM experience has made me a better lecturer.

So, if you find yourself wanting (or needing) to teach a class, consider honing your DM skills before you start. It's worth it.

Acknowledgements
I thank Lucy Kwok for the title, inspiration and usual humour. A warm thank you to my RPG friends (both here in Japan and abroad) for countless hours of fun and for not having any shame.