I had a quick read of the article. Supposedly in the worst case scenario (if your income is over 40 million yen) your total taxation amount can be over 50%.
However if you earn a more modest total income the tax rates are more lenient. 23% for less than 9,000,000 yen. If I made that much in a year I wouldn't mind paying 23% tax. I don't think it's overly high. But, if you're already on a large salary, trading bitcoin isn't the best way to invest (unless you make a profit so large it outweighs the tax disadvantages).
The thing that sucks is that losses can't be deducted against other forms of income.
From what I understand, it also confirms that profits from trading currencies pairs are also taxable. Which also sucks.
"Starting in 2009, losses can alternatively be deducted from dividend income declared as "Separate Income" since the tax rate on both categories is equal (i.e., 20% temporarily halved to 10%)"
Does 雑所得 translate to "Separate Income" above? In that case it would seem like the rate is the same as capital gain, i.e. 20% flat.
I'd like to know as well since I have some capital losses to offset and a dangling Bitcoin, so...
"Starting in 2009, losses can alternatively be deducted from dividend income declared as "Separate Income" since the tax rate on both categories is equal (i.e., 20% temporarily halved to 10%)"
That's talking about capital gains on stocks. The tax office quote I posted above says that Bitcoin profits are treated as income, not as capital gains. So the wikipedia article does not apply to bitcoin, I think.
Bitcoin is becoming a bubble. It wasn't so bad before but going into 2018 I can see it getting really crazy. That's why I'm diversifying into start-ups with real, working applications. The four I'm currently in are Omisego (p2p payments), Power Ledger (p2p selling and buying of solar energy etc.), Horizon State (a platform for trustless voting - think national elections etc.) and LockChain (think AirBnB but 20% cheaper due to there being no middleman). As opposed to Bitcoin, they all have working products, plans, brilliant people and active engagement with their communities. Much more comforting than holding BTC in my opinion.