At block 5,900,000 on May 29, 2018, Ethereum Classic permanently removed the exponential difficulty bomb via ECIP-1041. This was one of the most consequential protocol decisions in ETC's history.
What Was the Difficulty Bomb?
The difficulty bomb was an exponential term in the block difficulty formula: 2^(floor(block_number / 100,000) - 2). As block numbers increased, this term grew exponentially, eventually making block times so long that the chain became unusable. It was originally designed to force the network to upgrade — specifically, to transition to proof-of-stake.
ECIP-1041: Complete Removal
Unlike Ethereum, which delayed the bomb five separate times (Byzantium, Constantinople, Muir Glacier, Arrow Glacier, Gray Glacier) before finally transitioning to proof-of-stake in September 2022, ETC removed the bomb coefficient entirely. The exponential term was set to zero permanently.
Result
- Block times stabilized at approximately 13 seconds without artificial pressure
- No future "ice age" events can occur
- The network cannot be coerced into consensus changes via difficulty manipulation
Significance
This was a deliberate sovereignty decision. By removing the bomb, ETC committed at the protocol level to proof-of-work consensus. The network's consensus mechanism is now a choice, not a deadline — upgrades happen because the community evaluates them as beneficial, not because inaction makes the chain unusable.