It will surely affect ICOs on a wider scale because Japan is one of the countries who gives a strong support on cryptocurrencies. But on the other hand, I don't think it will affect bitcoin at all. It's fine for me if they ban all ICOs as long as their stand and support on btc is firm. And it's a good thing to regulate ICOs in the first place because there have beeb countless that sprouted and it's not that easy to spot the good and legit ones. And one drastic and effective step is banning all of it instead of dissecting each one by one.