Question: what is the difference between master grade and high grade gundam?
Answer: High Grades (HG) are 1:144. Master Grades (MG) are 1:100. Now, there are a few lines of HGs that are 1:100 in scale but they are legacy. The HG moniker are no longer given to 1:100 kits today, though old 1:100 HGs are still produced periodically.