Bitcoin Forum
November 09, 2026, 09:55:22 AM *
News: Latest Bitcoin Core release: 32.1 [Torrent]
 
   Home   Help Search Login Register More  
Pages: [1]
  Print  
Author Topic: [ANN][BIG] BigCoin - independent SHA-256d PoW chain. No ICO, nothing for sale  (Read 126 times)
takamoto_bigcoin (OP)
Newbie
*
Offline

Activity: 5
Merit: 0


View Profile
November 01, 2026, 08:19:56 AM
Last edit: Today at 09:26:14 AM by takamoto_bigcoin
 #1

BigCoin is an independent proof-of-work blockchain, forked from Bitcoin Core 31.1, with its own genesis block mined on 21 Oct 2026. It shares no history with Bitcoin. It has been running continuously since launch and is past block 6,000 at the time of writing.

There is no ICO, no presale, no airdrop and nothing for sale. I am announcing it here because this is traditionally where one announces such things.

What it is

- A full fork of Bitcoin Core 31.1 ("BigCoin Core"), MIT licensed, full source published with every release at http://133.242.139.204/downloads
- A fully independent chain: own genesis, own network magic, own ports and address formats
- Bitcoin's economics unchanged: 50 BIG per block, halving every 210,000 blocks, 10-minute target, 2016-block retarget
- All Bitcoin softforks (SegWit, Taproot, ...) active from genesis

What it is not

- Nothing is for sale. There is no ICO, no presale, and I will never sell my own coins
- There are no promises. I make no claims about what BIG is worth or will ever be worth
- Nothing technically novel. If you are looking for innovation, this is not it. It is a small, clean, honestly run chain - that is the whole pitch.

Founder reward - full disclosure

Block 1 pays a founder reward of 1,000,000 BIG to my address. This is hard-coded in consensus, documented in the README, and displayed in a permanent banner on the block explorer. Including it, the supply cap is about 22,000,000 BIG. These coins are not for sale - my policy is the original one: publish the software, mine, maintain, and never sell.

Specifications

Code:
Ticker            BIG
PoW               SHA-256d (same as Bitcoin)
Supply cap        ~22,000,000 BIG (21M mineable + 1M disclosed founder reward)
Block reward      50 BIG, halves every 210,000 blocks
Block interval    10 minutes target, retarget every 2016 blocks
Launch difficulty CPU-minable (genesis nBits 0x1f00ffff)
P2P port          8338
Addresses         bech32 "big1..." / base58 starting with "B"
Genesis (21 Oct 2026)
  000086c5bc212db5bf8760b3fb3a30dfcd6af76257fd529814bc032c8134424d

Links

Downloads - Windows and Linux binaries, full source, and the SHA256 of every file: http://133.242.139.204/downloads
Block explorer: http://133.242.139.204/
Seed node: 133.242.139.204:8338

These, plus this thread, are the only official channels. There is no Telegram, no Discord, and no token on any other chain. Anything else using the BigCoin name is not me.

Running a node

Windows: download the release zip and run bitcoind.exe - the bundled bitcoin.conf already points at the seed node.
Linux: build from source exactly like Bitcoin Core (the build docs are inside the source archive).
Manual connection: addnode=133.242.139.204:8338

Mining

The chain launched CPU-minable. A miner with real hardware showed up within hours of the v1.0 release and difficulty has been rising at the maximum allowed rate ever since, so the CPU era is effectively over. Standard solo mining works (getblocktemplate, or the built-in generatetoaddress RPC). There is no pool; anyone is free to run one, but it will not be mine.

Known quirks, disclosed

Bitcoin's retarget arithmetic was never designed for a CPU-minable genesis target: the 256-bit multiplication overflows while the target is very large, which made the first retarget jump x21 instead of the expected x1.24. Every node computes the same result, so consensus was never at risk, and difficulty has since risen out of the affected range. v1.1 fixed a header-sync issue this caused, and also pins the hashes of blocks 1 / 1000 / 2000 (replacing the checkpoint system that upstream removed), so settled early history cannot be reorganized. Details are in the release notes.

Why

I wanted a chain run the way the original was run at the start: release the code, mine, keep it alive, sell nothing, promise nothing. Whether that is worth anything is not for me to say.

Questions are welcome, including hostile ones. I will answer honestly.

- Masashi Takamoto (note: the bitcointalk user "bigcoin77" is not me)
takamoto_bigcoin (OP)
Newbie
*
Offline

Activity: 5
Merit: 0


View Profile
November 01, 2026, 11:06:45 AM
Last edit: November 02, 2026, 12:22:13 PM by Welsh
 #2

v1.2 released - GUI wallet

BigCoin Core v1.2 adds the standard Qt GUI wallet (bigcoin-qt.exe) to the Windows release, so the command line is no longer required to receive, hold and send BIG.

- Download: https://github.com/bigcoin77/bigcoin/releases
- BigCoin-win64.zip SHA256: c1d57735ce5e13866543a88c06a2fd898794cfd5a02c0fd108a0f9cb31754dc0
- No consensus changes. v1.0 / v1.1 nodes remain fully compatible; upgrading is optional.
- First launch asks for a data directory - copy the bundled bitcoin.conf there and it connects to the seed node automatically.

Network status at the time of writing: past block 12,000, two independent miners, and difficulty still rising at the maximum allowed rate every period.

- Masashi Takamoto

Weekly status update — 2026-11-02 (all facts verifiable on-chain)

Network
- Block height: 17,321
- Difficulty: 5.27 — the first upward retarget triggered at block 16,128
  (1.32 -> 5.27, the x4 per-period limit). The adjustment worked as designed.
- Next retarget: block 18,144
- Total supply: 1,866,000 BIG of 21,000,000 (~8.9%)
- Mempool: 0

This week
- An independent miner joined and at peak pushed network hashrate to roughly
  1.5 GH/s, mining several thousand blocks before going quiet. Two distinct
  coinbase addresses appear in the last 400 blocks.
- Independent nodes from several countries connected to the seed and stayed
  in sync.
- Official site is now live: https://bigcoin77.github.io/bigcoin/
- Latest release remains v1.2:
  https://github.com/bigcoin77/bigcoin/releases

Ground rules, unchanged: nothing is for sale, no exchange listings are
sought, no price talk. The founder mines openly; every founder block is
visible on-chain. If you want to participate, run a node or point SHA-256d
hardware at the chain.

Explorer: http://133.242.139.204/
Seed node: 133.242.139.204:8338
takamoto_bigcoin (OP)
Newbie
*
Offline

Activity: 5
Merit: 0


View Profile
November 07, 2026, 09:17:56 AM
Last edit: November 07, 2026, 12:27:20 PM by takamoto_bigcoin
 #3

v1.4 released — required upgrade: ASERT difficulty hard fork at height 17,325 (now live)

What happened
- The independent miner that drove difficulty up to 5.27 in early November went quiet. With the original 2016-block retarget, the remaining hashrate faced roughly 21x more difficulty than it could sustain, and the chain stalled at height 17,324 for about five days.
- This is the known weakness of Bitcoin's retarget rule on a small chain, so BigCoin now uses ASERT (aserti3-2d, the per-block difficulty algorithm Bitcoin Cash has run since 2020) with a 2-day half-life.

The fork
- v1.3 (2026-11-02) shipped ASERT scheduled for height 18,000. A stalled chain would never have reached it, so v1.4 moves activation forward to height 17,325 — the first block after the stall point. No existing blocks are reorganized.
- The fork is live and verified on-chain: block 17,325 was mined on 2026-11-07 at ASERT-computed difficulty 5.217, and block 17,326 followed at difficulty 0.881. Difficulty now adjusts every block and converges back to the 10-minute target on its own — if hashrate leaves again, the chain recovers automatically instead of freezing.

Action needed
- Nodes running v1.3 or older do not follow the chain from height 17,325. If you run a node or miner, please upgrade to v1.4. (A couple of older nodes are connected to the seed right now — this post is mainly for you.)

Downloads
- GitHub is temporarily unavailable (account review in progress, support ticket open). Until it is restored, binaries and full source are served from the explorer mirror:
- http://133.242.139.204/downloads
- BigCoin-win64-v1.4.zip — SHA256: ed3efd7168c25e5e5b1f29a481f8eb39326bc6a29708c924f6e62199c688d306
- bigcoin-source-v1.4.zip (full source, tag v1.4) — SHA256: c7680392269ea09060caa01aa871535c7d8c2559c3d0c60a873573ef5da08d44

Unchanged: 50 BIG per block, halving every 210,000 blocks, ~22M cap including the disclosed 1M founder reward, explorer http://133.242.139.204/ , seed node 133.242.139.204:8338. As always: nothing is for sale, no exchange listings are sought, no price talk.

- Masashi Takamoto


v1.5 released — maintenance only, fully compatible with v1.4

No consensus changes, and nothing in the ASERT fork above is affected. v1.4 nodes do not have to upgrade. Two practical fixes:

- The solo-mining helper script (mine-bigcoin.cmd) is now bundled inside the Windows zip. Put your own big1 address in it, double-click, and it creates the data directory, starts the node, creates a wallet and starts mining — no command line needed.
- The shipped binaries no longer carry the build machine's local directory paths. The compiler embeds absolute source and debug paths into every executable; those are now stripped. Nothing about the code itself changed.

Downloads (GitHub is still under account review, so the explorer mirror serves them):
- http://133.242.139.204/downloads
- BigCoin-win64-v1.5.zip — SHA256: 2077bf3e39117992443c3bc70700a8327b0280f790f3682b74fa08e62938d1cf
- bigcoin-source-v1.5.zip (full source, tag v1.5) — SHA256: 5cd3148e75433cdad49ed7a669383511a2635f29287356e0d6c091d0b9303ae6

The binaries are unsigned, so some antivirus products sandbox or flag them on first run — this is not new to v1.5. Check the SHA256 above, or build from the source zip if you would rather not trust a binary.

Network status at the time of writing: height 17,403, difficulty 1.01 after ASERT converged, blocks arriving on schedule again, and three distinct coinbase addresses in the last 300 blocks — including an independent miner that started right after the fork.

- Masashi Takamoto
takamoto_bigcoin (OP)
Newbie
*
Offline

Activity: 5
Merit: 0


View Profile
Today at 08:24:08 AM
 #4

Weekly status update - 2026-11-09 (all facts verifiable on-chain)

Network
- Block height: 18,134
- Difficulty: 3.13, recalculated every block
- Total supply: 1,906,650 BIG of 21,000,000 (~9.1%)
- Block spacing: 5.1 min over the last 144 blocks, 4.0 min over the last 500
- Mempool: 0

v1.7 is published today, and it changes the proof-of-work algorithm
Up to height 19,499 BigCoin uses double SHA-256, exactly like Bitcoin. From
height 19,500 it uses yespower 1.0 instead: N=2048, r=8, personalisation
string "BigCoin/yespower1.0", computed over the same 80-byte block header.
Every hash needs 2 MiB of memory.

Why. This chain's difficulty is about 3.1, which is roughly 44 MH/s of
SHA-256. A hobby single-chip miner, the sort sold as a desk ornament at about
1.2 TH/s, is some 27,000 times that; a second-hand datacentre unit runs 13 to
100+ TH/s, which is one to two further orders of magnitude on top. Either
owner could take every block for as long as they cared to, or rewrite recent
history, for the cost of the electricity - and no difficulty rule fixes that
on a chain this small, because difficulty cannot tell one miner from another.
yespower needs memory that a SHA-256 ASIC does not have, so that hardware
cannot participate at all: a block it produces is invalid, not merely late.

What this is not. It is not a claim that BigCoin is ASIC-proof for ever.
Someone can build hardware for yespower. It would have to carry the memory,
which is most of what makes a general-purpose CPU expensive, so the gap would
be a small multiple rather than the four-to-six orders of magnitude a SHA-256
ASIC enjoys here today. That is the whole claim, and I would rather state it
that narrowly than sell you a guarantee I cannot keep.

What it does not fix either. Heights below 19,500 stay double-SHA256 for
ever, so a fork rooted in that range can always be mined at ASIC speed. The
highest pinned block in v1.7 is 17,750, which caps how far back such a fork
can be rooted; a fork from there would still have to out-work the honest
chain from 17,750 on and would arrive as a reorganisation up to 1,750 blocks
deep by the time the switch happens, which no node applies quietly. That is a
bounded residual risk, not a closed hole, and the only thing that shrinks it
further is a later release pinning into the window.

The difficulty at the switch is set by hand, once
The old nBits measures double-SHA256 work and means nothing under yespower,
so the ASERT schedule restarts from a hand-set target at 19,500: 6,000,031
hashes per block, i.e. one block per ten minutes at 10,000 H/s. For scale, the
16-thread desktop this release was built on works out at roughly 5,000 H/s
across all of its threads, so that target assumes something like two such
machines are mining. Read that as an estimate of my hardware rather than a
benchmark of yours: yespower is bound by memory bandwidth, not clock speed, so
the spread between CPUs is wider than their specifications suggest.

That is deliberately on the hard side, and the asymmetry is the reason:
setting it too easy would mint coins quickly and cannot be undone, because
ASERT can only tighten by 0.24% per block. Setting it too high costs slow
blocks that fix themselves. So expect the first blocks after 19,500 to come
slowly - possibly for a day or two - while difficulty finds the real CPU
hashrate. It eases every block, and faster than that if a gap passes six
hours, which is the other change in this release.

Also in v1.7: the stall rule, from height 18,000
ASERT as shipped in v1.4 fixes the next block's target the moment its parent
exists - the elapsed time it measures runs to the PARENT'S timestamp. So
while the chain sits waiting, nothing eases. A difficulty left behind by a
miner who stopped does not decay; it stays where it was until somebody finds
one block at it. That is why height 17,324 froze for 5 days 3 hours at the
start of this month rather than slowly recovering, and v1.4 only cleared it
because I hand-moved the ASERT anchor. The next time it happens I might be
asleep.

From height 18,000 the elapsed time is max(parent's timestamp, candidate's
timestamp - 6 hours). Below six hours of silence that is byte-identical to
the old rule. Past six hours the target eases with real time on its own,
halving every two days, so a stranded difficulty clears itself. A three-day
visit from an ASIC followed by it unplugging used to leave a difficulty whose
expected wait for the next block was about 140 days; it now recovers in about
11 days with no intervention from anyone, including me.

What it costs you:
- Block timestamps are already capped at 2 hours ahead of real time, so the
  most anyone can gain by dating a block forward is 2^(2h / 2 days) = 2.9%
  less work. It does not compound, because the ASERT anchor is fixed, and it
  is a level shift available equally to everybody rather than a per-block
  subsidy to whoever lies hardest.
- Mining software must stop rolling the timestamp while keeping the old
  nBits, because from 18,000 the required nBits depends on that timestamp.
  getblocktemplate no longer advertises "time" as mutable at that height. Any
  miner built on generatetoaddress, including the scripts I publish, needs no
  change: it asks for a fresh template each round, which is also how it picks
  up the easing during a stall.

Height 18,000 is behind the tip by the time you read this, which is on
purpose: for every gap shorter than six hours the new rule computes exactly
the same nBits as the old one, so v1.7 validates the chain as it already
stands, block for block. I check that before publishing rather than assuming
it - if any gap at or above 18,000 had reached six hours, this release would
have been held back instead of shipped.

Both mining scripts are new, and worth taking
Every version before v1.7 waits for the node to report that its initial block
download has finished. A node started while the chain itself is stalled never
reports that, so the one moment the chain most needs another miner was the one
moment the old script refused to mine. That is fixed.

They also ask the node which algorithm the next block needs instead of
assuming one, and size each mining call by timing the previous one - which
they have to, because a yespower hash takes milliseconds where a double-SHA256
hash takes a fraction of a microsecond, and no fixed setting suits both sides
of 19,500.

One consequence is worth knowing before you judge the switch on per-hash costs
alone. These scripts drive the node's own generatetoaddress, which rebuilds and
re-serialises the block for every nonce it tries. That overhead is trivial
beside a yespower hash and dominant beside a double-SHA256 one, so today the
scripts reach well under what your CPU could do in a tight SHA-256 loop, and
after 19,500 the same code runs at close to the hardware's full yespower rate.
A CPU miner using what I publish therefore gains more at the switch than the
two algorithms' raw costs by themselves imply.

Unlike last week, the scripts are NOT byte-identical to the previous ones.
Replace them. The standalone downloads are versioned from now on
(mine-bigcoin-v1.7.cmd, mine-bigcoin-v1.7.sh) so the older files keep
working for anyone who linked to them; inside the packages the names are
unchanged.

What you have to do
Upgrade to v1.7 before block 19,500. At the pace of the last 144 blocks that
is about five days out, on the order of 14 November, but that estimate moves
with hashrate, so watch the height and not the date:

  bigcoin-cli getblockcount

Nodes on v1.5 or older stop at 19,500. Because it is the algorithm that
changes and not a difficulty rule, they do not merely fall behind: the hashes
they compute are no longer the ones consensus asks for, so they can neither
follow the chain nor mine one valid block past that height. The same is true
of any external miner or stratum setup speaking SHA-256d.

Upgrading is a binary swap and nothing else. The chain data on disk does not
change, so there is no reindex and no resync: stop the node, replace the
binaries, start it again. That holds even if you only notice after 19,500. A
node that rejects those blocks rejects them at the header, before anything is
written to its block index, so it has no bad verdict stored to undo - it
simply carries on from where it stopped once the binary understands what it is
being sent. You can read that for yourself in src/validation.cpp,
AcceptBlockHeader().

There is no v1.6 download, and the gap in the numbering is not an oversight.
v1.6 was built with the stall rule but without yespower; publishing it would
have handed you one more binary that dies at 19,500, so it was replaced by
v1.7 before release and never distributed. The published versions are v1.3,
v1.4, v1.5 and v1.7.

Your node will tell you where the switch is and which algorithm it expects
next, so you never have to take my word for it:

  bigcoin-cli getblockchaininfo     ->  pow_algo, yespower_activation_height

The seed node runs v1.7. The source is published with the binaries, so you can
read the change instead of trusting the description: src/pow.cpp,
src/crypto/yespower/ (vendored 1.0.1, with its provenance and local patches in
that directory's README.md) and src/kernel/chainparams.cpp.

Mining distribution
Coinbase addresses over the last 200 blocks, 6 distinct:

  179  89.5%  one address        not mine
   15   7.5%  one address        mine
    6   3.0%  four addresses     none mine

Over the last 500 blocks, 11 distinct addresses: the largest holds 86.6% and I
hold 8.6%. One address therefore accounts for roughly six blocks in seven,
which is enough to reorganise the chain at will. It is not me, and me saying so
does not make it safe. If you are considering mining here, that is the single
most important number on this page, and it is the reason independent hashrate
matters more than anything else I can ship.

I publish no addresses but my own; every figure above is reproducible from the
explorer in a few minutes. From 19,500 every miner needs yespower, whatever
hardware they are using today. I do not know what that will do to this table
and I am not going to pretend otherwise.

My own holdings, unchanged and still disclosed
My wallet holds 1,008,001 BIG, which is 52.9% of everything in existence,
across two addresses:
  big1qe2v5u9aqhafy85pxet8cpzzxyqgxxykqykj5gh  101 blocks, heights 1-101
  big1qycz9vmq49wuxkvl6v2tdnudglnfaxy7jd84xc3   80 blocks, heights 102-18,132
That total includes 200 BIG of rewards I cannot spend yet, because a coinbase
output matures 100 blocks after it is mined. I count them anyway: the supply
figure at the top of this post counts unmatured coinbases too, and the honest
way to state your own share is the one that does not quietly leave part of it
out of the numerator.
The first address includes the block 1 reward of 1,000,000 BIG, which was
disclosed from day one and is visible to anyone:
http://133.242.139.204/block/1
I have mined 1,009,000 BIG in total. The 999 BIG difference is the faucet:
1,000 BIG out to fund it, and 1 BIG back in, which is the single test claim I
made yesterday to confirm it actually pays. Nobody else has used it yet.
Nothing has been sold. Nothing is for sale. There is no exchange, no listing
application, and no mechanism by which I take money from anyone.

New this week - faucet
The explorer now has a faucet: http://133.242.139.204/faucet pays 1 BIG per
address, once per 24 hours, up to 50 BIG a day across everybody, funded with
the 1,000 BIG noted above - so you can see a transaction land in your own
wallet before you commit a CPU. If it tells you the daily budget is spent,
that is what has happened; it refills the next day.

v1.7 downloads
  BigCoin-win64-v1.7.zip           26.1 MB
  sha256 501613b628252dfcac7315dd2256332b0388f19ef44970f0e3794d088c9444d8
  bigcoin-linux-x64-v1.7.tar.gz    9.6 MB
  sha256 753399bf4d183ecc94e17404c475b25c5201bb2b7762fb98600332720691e0cb
  bigcoin-source-v1.7.zip          15.4 MB
  sha256 954390fb3dd8a3dc6e1feaf0469294ae5ff4957ae8de5117edf01923ba936125
  bigcoin-source-v1.7-unix.tar.gz  14.0 MB
  sha256 cbae78fca9c0953f3381e6e6d27d7c8dce73fdbb38c1d8e60e780b7d7aa98926
  mine-bigcoin-v1.7.cmd            21.6 KB
  sha256 b4973f0c5c6a6f59c276f899a21a7453a60e35e3b916d222e55fa27647c4bf26
  mine-bigcoin-v1.7.sh             17.4 KB
  sha256 67d55214e84a5571358c09d2c875f0b49d94a08307ac32e93e79cc56fec574dd

Ground rules, unchanged: nothing is for sale, no exchange listings are
sought, no price talk. If you want BIG, mine it.

Downloads:    http://133.242.139.204/downloads
Mining guide: http://133.242.139.204/mining
Explorer:     http://133.242.139.204/
Faucet:       http://133.242.139.204/faucet
Seed node:    133.242.139.204:8338
solarsurfer
Jr. Member
*
Offline

Activity: 86
Merit: 2


View Profile WWW
Today at 08:57:30 AM
 #5




BigCoin (BIG) – no longer mined at Shears Mining

From block 19,500 (expected around 14 November), BigCoin changes its proof-of-work from SHA-256 to yespower, a CPU-only algorithm. After that,
blocks found by SHA-256 hardware – Bitaxe, NerdMiner, ESP32 and ASIC miners – are no longer valid on the BigCoin chain.

As a SHA-256 pool, we have closed our BigCoin port (3790) and removed BigCoin from the pool, effective today.

Thank you to everyone who mined BigCoin with us – SHA-256 miners secured the chain through its first 18,000 blocks. Any BIG you mined is safe in your own
wallet.

Looking for another coin your ESP32 or Bitaxe can find real blocks on?
See our low-difficulty coin list: https://sha256-mining.shears.co.uk/coins.php


I would like to state however, we like supporting coins that start up, by mining ourselves, and setting up a mining system that also allows other people to mine by SHA256 (Bitaxes esp32 etc). If dev teams find our help to promote a coin useful, then I find it alarming that coin dev teams take away the help we provided to them during launch day of their coin, by removing SHA256 from mining, and not only that, but an early stage in the coins development. It also upsets people who mined this coin ! DEV TEAMS NOTE  !

Just my thoughts that doesn't need a reply !

Pages: [1]
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!