Hi
I am selling semi double mattress (120cm x 195cm x 17cm) for 7500 yen. I bought it two months ago. Here is the amazon link
https://www.amazon.co.jp/gp/product/B01LBYNPN2/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
If you are interested, here is my email: tamer.gph@gmail.com. I live in Imagiku near the police station.
Thanks in advance