Originally Posted by
Ghoulish
From what I've seen, the only way around a reentry sanction is with a "voluntary withdrawal" of attempting to entry the country. Again commonly offered in cases where the traveller wasn't attempting to violate the law but where discretion couldn't be exercised, like some minor criminal violation from long ago without the necessary exemption.
This was my thought as well. In the UK, the immigration officer can ask the person if they'd like to withdraw their request to enter the country, and as a result, no 'denial' placed in their record.
Given how poor the communication seems to have been during the incident, OP should explore whether their application to enter Japan was legally denied or whether they were considered to have voluntarily returned to the US after withdrawing their intention to enter Japan.