Re-entry into Japan

Hi, I want to go to Korea but I only have single entry visa which is good for 5 years stay here in Japan. With this can I go to Korea or I need to get multiple visa? I hope you can help me. Thanks.

https://www.japan-guide.com/forum/quereadisplay.html?0+165537

If you plan to leave and enter Japan within 1 year, no need for special paperwork.

You need to fill in this Embarkation and Disembarkation Card for Re-entrants available at the airport before you pass thru the immigration counter.
Make sure you tick the 'special Re-entry' section if you plan to return within 1 years from your departure date.
Keep the other half of the card stapled in your passport and show/return to immigration counter when you enter Japan again. You don't have to fill anycard on your way return to Japan, the other half is good.

The revised immigration regulation
http://www.immi-moj.go.jp/newimmiact_1/en/point_3-4.html

Sample of Embarkation and Disembarkation Card for Re-entrants
http://www.immi-moj.go.jp/re-ed/EDcard_leaf_en.pdf

You have a Status of Residence? i.e. living in Japan - surely that would superseded a single entry visa. That single entry visa is for what purpose - usually they are for things like tourism. Not enough information.
For example https://www.japan-guide.com/forum/quereadisplay.html?0+162424