Japan's largest hacking contest, aimed at fostering engineers able to counter cyberattacks, began Thursday with a regional preliminary in Yokohama.

SecCon 2013, organized by a nonprofit group and sponsored by the government, for the first time brought together university students and adult contestants who had advanced through earlier contests. Qualifiers from nine regional preliminary rounds to be held across Japan through December and an online version in January will compete at the national stage of the competition in March.

In the two-day round for the Kanto region, including Tokyo, more than 90 participants will be whittled down to 40 on the first day, then down to fewer than 10 on the second day. They will be required to solve basic problems concerning computer analysis techniques and website security, before having to solve more challenging problems as speedily as possible.