Here are some of the items on sale at Amazon.co.jp that we would like to recommend right now. The prices are as of the time of publication, so please check the sales page as well.
Fanless Quiet PC (42,000 yen → 35,700 yen)
A small fanless PC with an Intel Core i3-8145U CPU and a weight of only about 646g is on sale for 37,500 yen, which is 15% off from 42,000 yen at normal times. There are 6 days left, so think carefully, but be careful not to run out. By using an aluminum heat sink for the entire body, it is fanless and compact. Since it supports VESA mount, it can be installed on the back of the display and used like an integrated PC. The specifications are CPU Intel Core i3-8145U, memory 8GB, storage M.2 compatible 128GB SSD etc. OS is Windows 10 Pro 64bit. The interface is USB 3.0 x 2, USB 2.0 x 4, USB 3.1 (Type-C) x 1, HDMI x 1, DisplayPort x 1, Gigabit wired LAN terminal x 1, audio output x 1. It also has wireless LAN and Bluetooth. The main body size is W133 x D126 x H36 and the weight is about 646g. In addition, the model with a Core i5 7200U CPU is also 15% off for 46,740 yen. There is also a model with an i3-5005U CPU, but this one has a coupon of 39,999 yen to 2,000 yen off. Each has a different shape and weight, so you want to choose the one that suits your taste.
Fanless Quiet PC
42,000 yen → 35,700 yen