October 26, 2013. Difficulty rose by +46.02% to 390.93M from 267.73M.
Change
+46.02%
New difficulty
390.93M
Period length
9.6 days
Network hashrate then (7-day)
0.0 EH/s
Bitcoin price then
$187
Hashprice then
$235,306/PH/day
The 2,016 blocks before it took 9.6 days instead of 14, so the network had more hashrate than the difficulty assumed, and difficulty rose by 46.02%: one of the largest adjustments on record. For every machine on the network that is a pay cut of the same size until the next retarget.