I've just got long the Nikkei in after hours, average price around 12150. I've also bought some Feb Nikkei calls from 13500-15000 for a trade. I think we bottom today, and I think the Nikkei will rally 20%+ in the next 2 weeks. If I am wrong, and we have a 1987 style scenario, I will take some heat (I am not trading on margin yet, hence the calls) and then liquidate once the market has calmed down.
The reason I am buying now is because the only reason not to buy is fear, pure fear. It is scary to buy, no one else dares to buy, therefore if I am to call myself a trader, now is the time to have guts when others are scared, and step up to the plate. In a way I am almost indifferent to the result - I just know that, as a trader, I must buy now when panic is in the air.