I came across this method though a Japanese friend and it shows how Japanese pupils learn to multiply in maths lessons at a young age. The great thing is that uou do not need to learn Japanese to master this method!!
This method has proven very popular from the re tweets and the feedback I have received from fellow practitioners. To date it has been carried out as a Maths starter to thousands and thousands of Maths learners around the world. Pupils are taught this method in Japanese primary schools at a very early age to develop the ability to multiply large numbers.
It makes you ponder how we are teaching Mathematics to the kids of tomorrow in the west in comparison to the learning of Japanese students. I have had a few Japanese students confirm that this is how they learnt to multiply and have said that they found learning this method easy as all you need is the ability to draw parallel lines and count dots.
A good way to introduce this starter is to put up a map of the world and get learners to point out Japan on the map. As a teacher you can then move into how Japanese Pupils learn to multiply and follow one of the examples below. You do not need to learn Japanese but if you teach the Japanese words for multiply, divide, add and subtract it would be a great example of cross curricular activities and SMSC.