The easiest way to get this is to boost this with 1 partner while going for the
Choose the Chinese as your Civ.
Make sure you start with the default boosting settings:Infinite ResourcesPost Imperial Age
as starting AgeFast gameplayAll Visible500
Full tech tree on / off, no relevance for this achievement
Winning conditions: Standard
Both you and your opponent / boosting partner should do this and completely mirror each other:
-Build a some Castles and Town Centres and spam build 40-60 villagers and about 120 Chu Ko Nu.
-With your Villagers start building 2 Wonders.
-Select 60 Chu Ko Nu's and press ctrl + 1
-Select the other 60 and press ctrl + 2
-Now put both groups on Stand Ground mode
When the wonder completes, have your opponent attack it with 1 of his groups and repair the Wonder constantly. It takes about 17-18 fully repairs to get the amount of arrows required (If want to keep track of it then I recommend stop and starting the attack and repair rather than doing them simultaneously)
Both of you can now do this for 2 wonders at the same time to speed things up.
your 100.000 arrow achievement will pop mid game
so just be patient, this will take 10 min of shooting tops. Plenty of time to wait until the countdown goes beyond a 100 years and for you to kill it