Contract Servant|Blockchain TCG【Japanese dApps】

Japanese game developer Axcelmark announced TCG ‘Contract Servant’ using blockchain.

I introduce this game with advantage and disadvantage of blockchain games.

What is Contract Servant?


  • This is a strategy card game, allocating cards on 3×5 grids.
  • A part of cards is a token stored on blockchain and has an asset aspect.
  • Players can own cards and trade. 
  • New servants are born from other servants. 
  • There is non-tokenized cards. You can start to play Contract Servant without cryptocurrency.



I explain differences from existing card games.

Battle by allocating cards on grids

Contract Servant is a battle card game with allocating 8 cards on 3×5 grids. Cards have stats and JOB. They are put on front, middle or back line according to their JOB.

  • Defensive servants must be put on front line.
  • Attacking servants must be put on middle line.
  • Magic or Healing servants must be put on back line.

Allocating like that.

Attacking target line is decided by a chiper

At this stage, clear definition of the cipher is not announced. I guess each cards have secret parameters which decides target line. e.g. This servant intend to attack front, another one attack middle.


It’s a Warrior (attacking front), here is an Archer (attacking middle). Like that? Just a guessing!

Cards are tokenized. What is token?

Tokenized cards are non-fungible

In Contract Servant, cards are tokenized by using blockchain technology following ERC-721 standard.

Therefore, each card is unique one.

In existing card game saved cards data in their own server of the operating company. And the data is common. e.g. ‘The stats of card A (Offensive point 1,000 and Diffensive point 1,000) is same one for every player.

If the card A is tokenized, this card A (Offensive point 1,000 and Diffensive point 1,000) is only one in the world . It happens that there are cards of the same stats and name, but the lot numbers are different.

Tokenized cards are radable

Non-tokenized cards are stored in the server of the operating company. Although it seems to be owned by the player, in fact the player does not have ownership.

Tokenized cards are stored in blockchain. The player who know the secret key only can access.

And the player have ownership of the cards and can trade. There is a possibility earning money if you get valuable cards.

Tokenized cards are as assets because that is not substitutable and tradable.

New servants are born form other servants

As in the name, Contract Servant use smart contract of Ethereum. Simply speaking, smart contract is a program operating on blockchain system.

By using, this, you can generate new servant from tokenized servant on blockchain.

Disadvantage of tokenized cards

Tokenized cards are stored on blockchain of Ethereum. Therefore, it is expected that Ethereum (ETH) will be used for trading.

“I don’t have a Ethereum!! ”

You may think so.

Typically, it may be a little bit high hardle that buying Ethereum to play this game.

You don’t have to have a cryptocurrency!

However, this game prepares non-tokenized cards for beginners. So then, you can play without Ethereum.

  • Tokenized cards are for players who want to earn assets in cards and earn money by trading.
  • Non-tokenized cards are for other player.

You can choose both way what you want.

Impression of Contract Servant

I have a big expectation to these type games. Tokenized cards have a possibility to become your assets. Because of tokenized cards have unique stas, it’s difficult to make a ‘standard deck’. All player have to consider by themselves. I expect that both strategy and gaming will be high level.

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