At its core, a blockchain is a giant agreement machine. Every node needs to agree on what happened, in what order, and who owns what. This is called consensus, and it’s the backbone of trust in a decentralized network. Sui takes a fresh approach to this, optimizing for speed, scalability, and efficiency.

In most blockchains, all transactions — whether they’re simple or complex — go through the same heavy consensus process. That’s like making everyone wait in the same airport security line, whether they’re carrying a single backpack or an entire cargo container. Sui changes this with a dual-mode transaction system.

Here’s how it works: • Simple transactions — If a transaction only touches owned objects (belonging to one user), it doesn’t need full-blown consensus. Instead, Sui uses a faster mechanism called Byzantine Consistent Broadcast. This lets transactions settle almost instantly without involving the entire network in ordering them. • Complex transactions — If a transaction involves shared objects (accessible to multiple users), Sui uses Narwhal & Bullshark, its advanced consensus protocol. This ensures that everyone agrees on the exact order of events so there’s no risk of double-spending or conflicting updates.

The beauty of this design is that the network doesn’t waste resources ordering transactions that don’t need to be ordered. By skipping consensus for many common cases, Sui can process far more transactions in parallel than traditional chains.

Why does this matter? • Lower latency — Players in a game can upgrade their characters instantly without waiting for the entire network. • Higher throughput — A DeFi app can handle thousands of independent token transfers at the same time. • Cost efficiency — Users pay less in gas because the network isn’t bogged down by unnecessary consensus rounds.

Imagine a game marketplace where hundreds of players buy and sell items simultaneously. On most blockchains, each trade would stand in line, one after another. On Sui, if trades don’t touch the same shared resource, they can all be confirmed in parallel — like dozens of self-checkout stations instead of a single cashier.

This hybrid consensus model is one of Sui’s biggest innovations. It’s why the network can scale to millions of daily transactions without breaking a sweat — all while keeping security and trust intact.

---

If you’re ready, I can now do Article 4 — Move Language: Powering Sui’s Smart Contracts so we have the first four fully polished.