I have added these skills:

研究 Study
採掘 Mining
木こり Woodcutting
武器製作 WeaponCraft
防具製作 ArmorCraft

You will have the option to choose between each skill:

The "研究 Study" skill will increase your level.
The "採掘 Mining" skill will increase your ability to mine for ores.
The "木こり Woodcutting" skill will increase your ability to harvest wood.
The "武器製作 WeaponCraft" skill will increase your ability to create stronger weapons.
The "防具製作 ArmorCraft" skill will increase your ability to make stronger armors.