YJ is the shortened name for YongJun  (永骏),  aka Young Joe Toys.  YJ is an educational toy company based in China.  They have been designing magic cubes, puzzles and education toys for many years starting in 2005.  They did partner with MoYu for some time to take advantage of their manufacturing capabilities, but is now manufacturing good quality speed cubes completely independently.  YJ has created a number of really good quality magnetic WCA puzzles, and their MGC sub-brand has become really popular in the last couple of years and many of our customers have provided great feedback on the quality of their big cubes.