one-CPU-one-vote, the world's fastest PoW blockchain

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one-CPU-one-vote, the world’s fastest PoW blockchain

The meaning of Yumekawa

Sugarchain’s first node software is called Yumekawa (夢川). It can be translated in some ways.

  • “Yume (夢)” means dream and “Kawa (川)” means river. So it’s Dream River in japanese.
  • The second letter “Kawa” stands for “Kawaii (可愛い)”. In this case the meaning is Dreamy Cute.
  • Also Yumekawa replaces the word Core (ie: Bitcoin Core). We think it sounds a bit centralized.


Block time: 5 seconds
Difficulty: SugarShield-N510 (based on Zcash’s modification of Digishield)
Block reward: 42.94967296 SUGAR
Halving interval: 12,500,000 Blocks (approx. 2 years)
Total supply: 1,073,741,824 SUGAR
PoW algorithm: YespowerSugar (based on Yespower 1.0.1)
Port: 34230 (RPC 34229)
Premine: None (No ICO, No Presale, No Founder’s rewards)

The world’s fastest PoW blockchain

  • 5 seconds transaction speed
    • 120x faster than Bitcoin
    • 30x faster than Litecoin
    • 12x faster than Dogecoin
  • Stable transaction time:
    • Even if the hash power suddenly increases, the block time remains 5 seconds. It is against hash attacks.
  • Don’t worry about orphan blocks:
    • According to the testnet results, the average orphan rate is under 3% and no problem occurs.

A better halving

  • Halving is everything about limiting the total supply:
    • Bitcoin is valuable because its total supply has been strictly limited, unlike traditional currencies.
    • This total supply is controlled only by that halving. There is nothing else.
    • We made this halving better.
  • Block reward:
    • The block reward should be to a power of two, so that it halves correctly.
    • ie) 2^32/1e+8 = 42.94967296 SUGAR
  • Halving schedule:
    • Interval 12500000 blocks (5^8*32) which is about 2 years (exactly 1.9818619989852864… years).
    • The total number of times halving will occur is 33 times, over the span of approximately 66 years.
  • Total supply:
    • 1073741824 SUGAR in theory, and 1073741823.875 SUGAR in actual.
    • The difference is 0.125 SUGAR. One Satoshi (0.00000001) limitation makes this difference. In addition, this number is meaningful. FYI: 1 GB = 1073741824 Byte (2^30).
    • The total supply of Sugarchain is about 51 times greater than Bitcoin.
  • Halving Chart: Halving Chart
  • Halving Table: Halving Table


“31/Oct/2008 Proof-of-work is essentially one-CPU-one-vote”

Satoshi Nakamoto talked about the importance of decentralized mining in his whitepaper. We want to create a blockchain that anyone can do mining easily without any entry barriers.

  • CPU mining only
    • YespowerSugar (based on Yespower 1.0.1) is only for Sugarchain, not compatible with other Yespower coins.
    • The minimum difficulty (powlimit) is set low enough for two reasons. The first is to handle fast block time; The second is to allow mining on slow CPUs.
  • Mining efficiency:
    • According to the test results, the most efficient is using 8 threads on a single CPU.
    • YespowerSugar is more suitable for older CPUs, because it is essentially a multi-threading resistor. Suitable for smartphones and raspberrypi.
  • NO GPU: GPU mining is not possible.
  • NO ASIC: ASIC mining is not possible.

Other advantages

  • Native segwit (Bech32) address built-in by default: Starting with sugar1q...
  • Fast blockchain synchronization: Using sha256d in header indexing, the initial synchronization speed is as fast as Litecoin.


  • Disk space requirements:
    • Blockchain size growth is around 10 MB per day and around 3.65 GB per year.
  • Network rules:
    • To prevent fraud and timestamp attacks, nodes should be within 70 seconds of accurate internet time, or they will be banned.
  • Selfish mining & time warp attack:
    • Fraud techniques for manipulating timestamps are already known. We use a future time limit (FTL) to prevent this. Blocks that differ 60 seconds or more from the current head will be banned. (credit: zawy12)


  • Block time vs difficulty at first launching on testnet

    • To keep the block time 5 seconds, SugarShield-N510 adjusts the difficulty level. Unlike the Zcash’s modification version, we use a moving average of 510 blocks (about 42.5 minutes). It counts from block 1, an adjustment is made at block 511, and the actual control begins at block 512. (log: time-diff)
    • Blocktime vs Difficulty
  • Nonce distribution at first launching on testnet

    • The nonce is randomly well distributed. Difficulty changes but no bias. (log: nonce-diff)
    • Nonce vs Difficulty



Bech32 address is by default and strongly recommended. -t1 uses 1 thread. If you want more hash, increase this number.

	./cpuminer -a sugarchain -o stratum+tcp://POOL_ADDRESS:PORT -u sugar1q... -t1


Please contact us if you have a new mining pool.



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Sugarchain Yumekawa is released under the terms of the MIT license. See COPYING for more
information or see

  • Copyright © 2009-2010 Satoshi Nakamoto
  • Copyright © 2009-2018 The Bitcoin Core developers
  • Copyright © 2013-2019 Alexander Peslyak - Yespower 1.0.1
  • Copyright © 2016-2018 The Zcash developers - DigiShieldZEC
  • Copyright © 2018-2020 The Sugarchain Yumekawa developers