Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This build is tested and true. It can be used to make a high damage, physical "carry" designed to work in a team environment. The are no attack speed items in the build and Ashe does great without them. High damage and a bit of survivability(Flash/Ghost - Banshees or Guardian - Boots of Swiftness/4.5% Movement Speed Quints/3% Movement Speed Mastery) functioning amongst a team, will have you pounding out lethal arrows while being to maneuver into safe positions to do so.
What keeps you alive?
Comes with knowledge and the experience to use that knowledge properly. Play...watch streams and videos...learn about items and potential opponents.
2. Summoner Spells
Flash and Ghost, being excellent escape abilities when needed mean that while they are active, Ashe can stray into her lane a bit more freely to farm as usual...even when there is a "gank ready" jungler, or enemy around.
3. Movement Speed
Boots of Swiftness coupled with the 7.5% movement speed form Quints and Masteries keep Ashe traversing the map at a very respectable pace. Cover lanes for fallen teammates, setup a gank in another lane, or help an ambushed friendly jungler...all these things become easier when she can haul A$$.
4. Defensive items
A Banshees Veil is 100% effective in 100% of games Ashe is in. It is a great all around defensive item.
A Guardian Angel is a good option when the enemy team has very little magic and few, or no, diables(stuns, snares, taunts). Keeping an enemy like Yi(with "Ultimate" speed that helps him outrun you) from ripping you apart.