>>26716340She should probably talk to a US-based certified public accountant or tax attorney. There is no way she has to pay in taxes what she says she's paying unless she's not taking advantage of any of the egregious amount of loopholes and deductions that exist in tax law.
The United States has the most complicated tax system in the world and US citizens are expected to voluntarily disclose their income and determine the correct amount of taxes that they owe by themselves. Government audits go out to individuals that are suspected by the IRS of miscalculating their taxes and legal penalties await those that deliberately hide their income for the purpose of evading taxes. Due to this complexity, the wealthier you are, the more avenues you have to avoid what she is currently going through. It may be as simple as setting up the correct type of bank account, changing the method of how she is paid, or raising her maximum deductions or tax credits through some obscure process. She needs to consult a professional if she isn't doing so already.
Japanese taxes are rough with the highest personal income tax bracket being 45% for permanent residents on their worldwide income with an additional 2.1% surtax. When living in Japan, this is combined with a flat 10% tax rate for local governments leading to an overall tax rate of about 56% on all income over a certain amount. However, foreigners have it a bit better than others because they are only taxed on the income they make sourced from Japan. What Mori said lines up correctly with everything I've read about the income tax on a Japanese resident's Japanese-sourced income.
This website is pretty helpful in understanding what she'd be expected to pay:
https://taxsummaries.pwc.com/japan/individual/taxes-on-personal-income>In Japan, permanent resident taxpayers are taxed on their worldwide income. Non-resident taxpayers are taxed only on their Japan-sourced income. Non-permanent resident taxpayers are taxed on their income other than foreign-source income (in particular, potentially, on certain capital gains) that are not remitted into Japan plus potentially part of their foreign-sourced income that is paid in or remitted to Japan.>A non-resident taxpayer’s Japan-source compensation (employment income) is subject to a flat 20.42% national income tax on gross compensation with no deductions available. This rate includes 2.1% of the surtax described above (20% x 102.1% = 20.42%). A non-resident taxpayer may be subject to the local inhabitant’s tax at a rate of 10% if they are registered as a resident as of 1 January of the following year.The US is only one of two countries in the world where taxes are based on citizenship and not residency. So the reason that Mori is taxed twice at the maximum bracket in each country is because she is not paid as a COVER employee, but rather as a contractor. This is combined with the fact that COVER collects her channel's income first and then gives her half of it. If the order were reversed and Mori were to collect her channel's revenue from Google herself and then pay COVER half of that, she'd only be subject to paying US taxes as her income would be classified as overseas-sourced income. Alternatively, if she were to be officially employed by COVER, she would still be subject to both US and Japanese taxes, but the Japanese portion of her income taxes would be lowered to 30.42% instead of her current 56%. At least, that's my understanding. Most countries, including the US, have income tax treaties in place to prevent this kind of situation.
https://www.irs.gov/businesses/international-businesses/japan-tax-treaty-documents tl;dr: Mori is in the worst possible situation regarding the way she receives her income and she needs to meet with a US-based CPA or tax attorney that specializes in US citizens working abroad and specifically in Japan. Ideally, a professional could help her work with COVER to find a better method of paying her that would lower her taxes. There's no reason why she should have to pay 70-80% in taxes because she should be receiving US tax credits so that she is not being taxed twice. This goes for IRyS as well.
https://www.hrblock.com/expat-tax-preparation/resource-center/income/foreign/foreign-income-taxes/https://www.irs.gov/individuals/international-taxpayers/choosing-the-foreign-earned-income-exclusionForeign tax credit form:
https://www.irs.gov/pub/irs-pdf/f1116.pdf 
