It varies greatly on skill/pedigree (the two often, but not always, correlate). If you are poor to average you'll start at $50K-70k/year. If you're average to good you'll start at 70k-90k, and 90k+ if you're particularly good (about 150K is the maximum I've heard of, and that's more in modeling or quantitative development than straight programming). About a 10% bonus is normal in my experience, but that obviously varies based on skill/industry. There is also some give based on what sort of company/industry you want (e.g., I personally know someone who just this week turned down a six figure offer at a hedge fund for ~20k less doing AI research).

Those numbers are for a programmer in/near big cities (Boston, Silicon Valley, NY, etc). Revise them down ~10% for more rural/suburban areas (but it's harder to find work beyond code-monkey level at all in many of those places). And all this is based on my anecdotal experience, so figure there is likely some selection bias.

In my experience, between federal and state income taxes, FICA, and sales tax you'll lose ~50% of your of your income to the government. And we have to save for our own retirement (we expect nothing from social security) and our kids' college education (currently ~15k-30K/year tuition).

How are your taxes/retirement/etc in Japan?