DeFi Tax in Japan: Swaps, Liquidity and Yield Farming

DeFi is where Japanese crypto tax stops being arithmetic and starts being judgement. The published guidance covers the building blocks clearly. It does not answer every composite transaction, and pretending otherwise is how people end up with a number they cannot defend.

This guide separates the two: what the NTA has actually stated, and where you are reasoning by analogy and should say so.

The two rules everything else is built from

First, a swap is a disposal. FAQ section 1-3 covers exchanging one crypto asset for another and treats it as a taxable event, valued in yen. There is no fiat leg required and no de minimis for small swaps. A DeFi user who never touches yen can still have a full year of taxable disposals.

Second, rewards are income on receipt. FAQ section 1-7 covers mining, staking and lending, and brings the market value of the crypto received at the time of receipt into gross revenue, with the costs incurred deductible. That value also becomes the cost of those tokens, so selling them later is a second, separate event measured against it.

Those two rules, applied honestly, resolve most of what a DeFi user actually does.

Applying them to the common patterns

• DEX swap. Squarely within section 1-3. Disposal of the token given, valued in yen at the time.
• Yield farming rewards. Reward tokens arriving in your wallet are the section 1-7 pattern: income at the yen value on receipt, and that value becomes their cost.
• Lending interest. Section 1-7 names lending explicitly.
• Gas and protocol fees. Section 2-3 lists the necessary expenses for a crypto disposal as the cost of the asset disposed of and the fees paid on sale, and allows other expenditure only to the extent it is directly required for the disposal.

Where the guidance runs out

Depositing into a liquidity pool and receiving an LP token in return is not addressed by a dedicated Q&A. Whether that deposit is itself a disposal of the deposited assets depends on how you characterise the exchange, and the honest position is that this is a judgement call, not a settled rule. The same applies to LP token redemption, to impermanent loss, to wrapping and bridging, and to rebasing tokens.

What you can do is be consistent and be able to explain your treatment. What you should not do is adopt whichever characterisation is cheapest in each individual case. If your positions are material, this is the point to involve a tax accountant rather than a calculator.

The three things that make DeFi expensive in Japan

The rate. Crypto gains are miscellaneous income, aggregated with your other income and taxed at progressive national rates of 5% to 45% plus a flat 10% resident tax, so the effective ceiling is around 55%.

No offset. Under FAQ section 2-11, losses arising in the computation of miscellaneous income cannot be set against salary or other income, because the Income Tax Act restricts offsetting to real estate, business, forestry and capital gains income. A profitable farm and a failed one in the same year net off inside miscellaneous income, but a losing year does not reduce your salary tax.

Reward volume. Per block or per day reward accrual means hundreds or thousands of separate income events, each needing a yen value at its own timestamp. This is the part that cannot be done by hand and is the main reason DeFi users need software rather than a spreadsheet.

Cost basis method

Disposal cost is computed by the total average method or the moving average method, selected per crypto asset type. FAQ section 2-5 requires the election to be filed by the filing deadline for the year of first acquisition, and states that where no election is filed the method is the total average method. Section 2-6 sets out how to change it later.

For DeFi in particular the choice matters, because a high volume of same-token in and out over a year produces materially different results under the two methods.

Our Japan crypto tax guide covers the income rules, and the DeFi tax guide covers the mechanics across jurisdictions.

General information, not tax advice. DeFi treatment involves genuine uncertainty. Confirm your positions with a qualified Japanese tax professional.