GST is charged on supply of goods. You will be supplying goods from Mumbai to Bangalore, so you have to charge IGST on supply.
From Bangalore you can export goods to Japan.
You have not provided details whether Japan company have GST registration or not, second whether you have GST registration in Bangalore or not.
At current stage, it will be wise to take GST registration same warehouse for your company, you can ship goods to warehouse and post inspection export these goods.
Further Bangalore branch can take GST refund post export.
Sign up to discuss taxation, accounting and finance topics with experts from all over India.Join Discussion