I have used the google doc myself to verify the recipes. In the Weapons sheet you will see the line for two-handed axes in row 11. It clearly states that you need Blacksmithing 2 to craft it and that you get the one of two bonuses if you have Blacksmithing 5. I have tested it in the game and with Blacksmithing 2-4 the same weapon is created. With blacksmithing 5 one of two weapons are created; one with a damage bonus and one with a critical hit chance bonus. And to answer your question fragonard: It requires Strength 16.