Vietnam's JCM Projects: How the Joint Crediting Mechanism Works in Practice

The Joint Crediting Mechanism is Japan's bilateral carbon crediting programme, operated with partner countries including Vietnam. Japan finances or transfers low-carbon technology, the resulting emission reductions are verified under jointly agreed methodologies, and the credits are split between the two governments. For Southeast Asian developers it is the region's longest-running working example of what Article 6.2 cooperation actually looks like in practice.

JCM predates the Paris Agreement's Article 6 rules and was later brought into alignment with them. The structure is deliberately simple compared with the centralized UNFCCC route.

A joint committee of both governments approves methodologies. A project is registered against one of those methodologies, implemented, then verified by a third-party entity. Issued credits are shared between Japan and the host country according to an agreed split.

The bilateral design is the point: two governments can agree rules faster than 190 can. The trade-off is that credits are only as portable as the arrangement that created them.

Three things make JCM worth understanding even for a project with no Japanese counterparty.

It demonstrates that corresponding adjustments work operationally, not just on paper. The host country adjusts its accounts for the transferred share, which is the same mechanic Indonesia now applies under Perpres 110/2025.

It shows where methodology development actually happens in bilateral schemes — at the joint committee, not at the project. A developer's leverage is in bringing a well-evidenced methodology case, not in negotiating credit-by-credit.

And it establishes verification expectations that regional buyers increasingly treat as baseline.

One strand of Vietnamese activity concerns alternate wetting and drying in rice cultivation, a practice that reduces methane emissions from flooded paddies by allowing fields to dry intermittently.

The methodological challenge is instructive regardless of scale. Methane flux from paddy soil varies enormously with water table, soil type, organic inputs and temperature. Establishing a credible reduction requires either dense direct measurement or a well-calibrated model validated against direct measurement, and the sampling design determines how much of the claimed reduction survives conservative deduction.

This is the same problem that governs forest biomass: heterogeneity drives sampling intensity, and sampling intensity drives cost. Projects that stratify by the variables actually causing variance need far fewer measurement points for the same confidence.

Two transferable lessons.

Bilateral arrangements reward early engagement with methodology. By the time a methodology is fixed, a project's options are fixed with it. The developers who do well are those who understand the approved methodology's sampling requirements before designing the monitoring plan.

Verification standards travel. A regional buyer comparing Vietnamese JCM units against Indonesian SPE-GRK units will apply broadly similar tests: is the methodology recognised, is the sampling defensible, is uncertainty quantified, is the data chain traceable. The registry differs; the diligence does not.

1. Joint Crediting Mechanism overview — https://www.jcm.go.jp/ (accessed 16 Sep 2026)

2. Perpres 110/2025 and Indonesia's Article 6 pathway — https://www.trucarbon.co/perpres-110-2025 (accessed 17 Sep 2026)

3. Singapore Article 6 cooperation portal (regional context) — https://www.carbonmarkets-cooperation.gov.sg/our-art6-cooperation/ (accessed 16 Sep 2026)

Vietnam-specific figures in this draft are withheld pending primary-source verification.