Similarly, some people unlocked everyone's Lv3 weapons on the Master Quest Map and then easily farmed out Lv2 drops, allowing them to unlock the first Master Sword seal (the 10k one) a lot quicker. So as long as you can secure one drop of every weapon level for every character, you can unseal the Master Sword skills. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.