The IBM JX (or JXPC) was a personal computer released in 1984 into the Japanese, Australian and New Zealand markets.

The PCjx later had a BIOS upgrade chip, sold together with PC DOS 3.21, which could use the full 720 KB capacity of the diskette drives.

Some popular options for the PCjx were a 5.25" 360 KB capacity diskette drive, a 10 MB external hard disk (both of these as stackable units the same size as the JX itself) and a joystick.

The magazine stated that its compatibility with PCjr peripherals rather than the PC's, and joystick ports and audio, "suggests that IBM Japan is hedging its bets by pursuing a share of the easily saturated video-game sector".

BYTE concluded that "the JX will enjoy, at best, a modest and short-lived success—it's too little, too late" against more-sophisticated rival computers.

[4] IBM Japan advertised the JX as a home computer, but its sales didn't grow even in 1986.

According to the Nikkei Personal Computing journal, a distributor revealed the number of units sold was "around 2,000 units in Japan alone", and an industry insider expected "Sales to retail stores, overseas stores, IBM's employees, their family, and direct sales to large customers.

In Japan, the mainstream of Intel microprocessors was moving from the 8086 to the 80286, and computer enthusiasts considered the 8088 as a branch of them.

A developer of the JX insisted it was designed to run western PCjr softwares without modification, but few Japanese users wanted them.

The JX providing the Japanese text mode and word processor had the potential to expand into the small-business sector.

The JX was dedicated to be inexpensive for personal use, but it didn't suit consumers who preferred the fast response time for gaming.