Cardano has crossed one of the most consequential technical thresholds in its history. On June 23, the network launched the public testnet for its Leios scaling protocol — a milestone described as the most significant the chain has reached in years. The testnet carries the name Musashi Dojo, a nod to the 16th-century samurai philosopher Miyamoto Musashi. The timing is deliberately symbolic. Musashi was renowned not for speed, but for methodical discipline — and that is precisely the philosophy Input Output is applying to the most ambitious upgrade Cardano has ever attempted.
What Is Ouroboros Leios?
Ouroboros Leios is an optimistic consensus protocol that builds on Cardano’s existing Ouroboros Praos mechanism. Its core objective is to push far more transactions through the base layer without compromising the security model that Praos already provides, including resistance to an adversary controlling up to roughly half the network’s stake.
The architecture works by introducing a parallel processing layer. Under the hood, block producers continue to generate standard Praos blocks — called Ranking Blocks — on their usual schedule. When demand is high, they can also produce larger Endorser Blocks that reference extra transactions running in parallel. To manage bandwidth efficiently, an Endorser Block lists transaction hashes rather than full transaction bodies. Those Endorser Blocks are not trusted automatically: a stake-weighted committee votes on each one using BLS signatures, and only after an Endorser Block clears a high voting threshold are its transactions folded into the ledger through subsequent Ranking Blocks.
The throughput numbers are significant. The upgrade aims to push the network’s capacity from its current 4.5 KB/s to 200 KB/s — roughly a 65-fold increase. Input Output product manager Carlos Lopez de Lara confirmed the initial rollout will start at two to five times current throughput, with the full ceiling available as demand grows.
Cardano to launch Leios testnet under Musashi Dojo name
The Five Phases of Musashi Dojo
The testnet is structured into five distinct phases named Earth, Water, Fire, Wind, and Void. The Earth phase covers basic protocol design validation. Water focuses on parameter exploration. Fire is where Leios meets real-world conditions — the most critical stage for stake pool operators, involving broad testing of software, operating systems, architectures, and hardware. The Wind phase introduces adversarial testing. Void is the final preparatory stage before mainnet launch.
Developers and stake pool operators are being encouraged to participate early to help refine the system under live network conditions and prepare applications for the higher throughput environment. This is not a closed lab exercise — it is an open invitation to stress-test the protocol under real-world pressure before any code touches mainnet
Why Leios Matters Beyond the Numbers
The case for Leios is not purely technical. There is an explicit economic rationale: Cardano’s staking rewards rely on a reserve that shrinks over time. Higher throughput means more fee revenue, which the project views as the mechanism to keep paying stake pools once those reserves run low.
The scaling ambition is also embedded in Cardano’s long-range planning. The Cardano 2030 Vision targets growth from roughly 800,000 monthly transactions to more than 27 million. The current Praos base layer cannot reach that figure on its own. Leios is the engineering answer to that gap.
Funding for the upgrade is already locked in. In late May 2026, Cardano’s delegated representatives approved a treasury proposal of 27.7 million ADA — authored by Lopez de Lara and Sebastian Nagel — covering the transition of Leios from a testnet prototype to a mainnet-ready release candidate. Funds are released against milestones, and any unused ADA is returned to the treasury. The governance proposal passed with over 84% support from Cardano’s delegated representatives.
The Road to November
Input Output is targeting a mainnet hard fork as early as November 2026 following the test programme. That gives the Musashi Dojo phases roughly five months to do their job — validate the protocol, tune parameters, survive adversarial conditions, and deliver a release candidate that the broader network can upgrade to with confidence.
Alongside Leios, Cardano’s roadmap includes the Van Rossem Hard Fork in late June to July 2026, which will upgrade Plutus smart contract performance and add new cryptographic functions, as well as a Cardano Card launch in Q4 2026 enabling ADA and stablecoin spending via Apple and Google Pay.
A Technical Milestone in a Difficult Market
The launch arrives against a challenging backdrop. ADA hit its lowest level in five years this month, down roughly 35% over the past 30 days. Its all-time high of $3.09 came on September 2, 2021 — today’s price of around $0.16 sits 95% below that peak. The TapTools analytics platform shut down earlier this year, Cardano cancelled its 2026 Singapore Summit, and Charles Hoskinson issued warnings about potential failures among Cardano DeFi projects.
Cardano (ADA) Price Performance (Source: CoinMarketCap)
Yet the engineering has continued without pause. Leios removes the most persistent technical criticism of the chain: that the base layer cannot scale. Whether the market reprices over the next five months of testing, or waits for mainnet confirmation, remains the defining question for Cardano’s second half of 2026.
For a network that has long been critiqued for slow delivery, the Musashi Dojo testnet represents a turning point — one where the years of peer-reviewed research, formal specification, and deliberate development either begin to convert into measurable on-chain reality, or face the scrutiny of a live network for the very first time.
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