fiveoutofnine is the first 100% on-chain chess engine, where minters play against the smart contract. Each move is minted as an NFT, and accompanied by a generative art piece. The majority of the project's development and beauty is in its algorithms and code that enable such complex computing, so the art highlights its design and implementation.
If a king is missing, that is a non-fatal bug. You can continue minting without issues. I will address this on my Twitter.