[ANN] Bitcoin Coin Series (Half/Quarter/Dime/Nickel/Cent)

Bitcoin Coin Series (Half / Quarter / Dime / Nickel / Cent)
CPU-mined Bitcoin forks | no premine | mainnet live since 2026-11-06

Bitcoin Coin Series is an experimental, unofficial set of five Bitcoin Core forks. It is not affiliated with Bitcoin, Bitcoin Core or any Bitcoin organization.

Why

Bitcoin's supply is fixed at 21 million. As its value grows, one coin moves further away from everyday amounts: a cup of coffee is 0.000034 BTC. Sub-units like satoshis are one answer. This project tests a different one: five separate coins with different unit sizes (1/2, 1/4, 1/10, 1/20 and 1/100 of a bitcoin, like US coins). All five start at the same moment under the same rules, are mined together on ordinary computers and are given free to existing bitcoin holders. The question is simple: given the same start, how do people take up and use different units?

It is a long-running experiment, not a business. It does not compete with Bitcoin. The fair start (genesis tied to a future Bitcoin block, no premine) exists so that the experiment is not distorted by insiders, including me.

The five coins

Coin	Ticker	Multiplier	Max supply
Bitcoin Half	BTCH	x2	42,000,000
Bitcoin Quarter	BTCQ	x4	84,000,000
Bitcoin Dime	BTCD	x10	210,000,000
Bitcoin Nickel	BTCN	x20	420,000,000
Bitcoin Cent	BTCC	x100	2,100,000,000

What it is

Bitcoin Core v31.1 plus 11 small patches. All source patches are in the repository.
Proof of work is RandomX v1, so it is mined on ordinary CPUs. One computation mines all five chains at once (merged mining).
A block every 10 minutes. Difficulty adjusts every block, with stall relief if no block is found for an hour.
Block rewards follow Bitcoin's schedule from height 840,000, times the multiplier.
Bitcoin holders at block 840,000 can claim the multiplied amount by signing with their own keys (BIP-322 or legacy signed message). A claim never moves bitcoin.
Signatures include a chain identifier, so transactions cannot be replayed between chains or onto Bitcoin.

Fair start and honest status

The genesis of each chain contains the hash of Bitcoin block 974800, which did not exist when the code was published. Nobody, including the issuer, could mine before that block appeared.
No premine and no developer allocation. There was no presale or fundraising, and the issuer does not sell coins or promise any price. Anyone who mines or claims coins is free to use or exchange them as they wish.
The mainnet launched on 2026-11-06. So far the issuer has been the only miner, at about 1,300 H/s on one desktop PC. All of the roughly 900 blocks so far (as of 2026-11-13) were mined by the issuer, for example about 5,600 BTCH. The issuer's reward addresses are listed in the README, so anyone can check them. Every new miner makes the chain less dependent on one person. That is the purpose of this post.

How to join (Windows)

1. Download the repository and copy the windows folder.
2. Download the Bitcoin Core UTXO snapshot of block 840,000 (about 9.8 GB, torrent or direct link in the README). The node checks its hash, so the source does not matter.
3. Run m1-start-mainnet.bat. It connects to the public node coinseries.duckdns.org, syncs and starts mining with all CPU threads.

Tested on a fresh laptop: from first run to mining took about 15 minutes, excluding the download.
Linux and other systems: build Bitcoin Core v31.1 with the patches in patches/.

Public node (all five chains): coinseries.duckdns.org, ports 21302 (Half), 21304 (Quarter), 21310 (Dime), 21320 (Nickel), 21400 (Cent).

Please note

This is an experiment. The coins have no promised value and there is no exchange listing.
To claim, sign a message in your own wallet. Never type a private key or seed phrase into any website or tool, including anything claiming to be from this project.

Repository: https://github.com/sentodaimon/coin-series
Specification, whitepaper (English and Korean) and manual are in docs/.

Questions and test reports are welcome in this thread.

- Sento Daimon