Japanese bonds mostly bought by citizens

It sucks money out of savings which reduced economic activities and consumption. QE seems not a major factor because their is enough savings to fill the budget gap. On the other hand, Japanese move their money outside to search for yields. This cuases inflation of asset in foreign contries. Also Japanese have trade surplus so it does not need to import and it produce everything it needs. As the bond build up, Japan will face similar issues. However, because Japanese are savers and Japan has high real productivity and low consumption, it can last longer.