1. Sumo wrestlers are celebrities in Japan and have a high status in Japanese society.  There is even a story that a famous film actress recently fell in love with a Sumo wrestler but his family didn't allow the wedding because she was considered to be from a lower class!  

2. Sumo wrestling is an ancient tradition which dates back at least 1500 years. Like most martial arts in the Far-east, it has its roots in the ancient monasteries. It was practiced by Shinto followers as a ritual for good harvest.    

3. The ring is made of clay with rice straw, symbolising good harvest. Before entering the ring, wrestlers throw salt in the air for purification and good luck. This is an ancient Shinto ritual and still practiced  throughout Japan. They also drink some water before entering the ring as part of the purification.  

4. After entering the ring, the wrestlers give each other respect by bowing, crouch facing each other, stretch their arms out showing their palm to confirm they're not concealing any weapons and their game is going to be 'fair'.  

5. They stretch their legs up in the air, stamp their feet and balance themselves to size each other up, slapping their bum and belly for dramatic effects!  

6. The rules are simple. First one to touch the floor with any part of his body (other than feet) or first one to go out of the ring loses. Most fights last a few seconds, only rarely going into minutes. Winners must not show triumphant gestures and losers must not show sulkiness or disappointment. They must always show respect for their opponents at all times.  

7. It's a lifetime commitment to be a Sumo wrestler with a highly disciplined life. They exercise intensively and  feed on high calorie diets - up to 10,000 calories a day.  Their traditional meal is called Chenkonabe (a type of hotpot) which they eat before going to sleep to help with weight gain. The average weight is 148 Kg and maximum is 265 Kg (42 Stones)! Consequently, the average life expectancy of a Sumo wrestler is 10 years younger than the average Japanese male - which is still surprisingly long given their size!  

8. Sumo referees also have a life time commitment. They start at the age of 16 and stay on until retirement. They wear distinctly colourful silk robes specific to their rank, with a sword carried to symbolise the seriousness of their decision. In the olden days they may have had to use it for a hari-kari, in case they made a bad decision! In the modern day, they would just hand in a resignation letter!  

Outside of the ring, the wrestlers are also required to wear a traditional attire at all times in public, with a specified hairstyle.  

9. There are a number of foreigners who compete at the highest level. The current champion is a Mongolian. Mongolia has produced a number of most celebrated champions in the last few decades! The other current ones come from places like Brazil, Korea, Philippines, Russia, Egypt, Czech republic (the 'skinny' Sumo wrestler weighing 100kg) and China.  

10. Watching sumo has been one of the most interesting days for me in Japan. It encapsulates the unique culture of old Japan and brings it to the present. The chantings, feet stampings, salt throwing, water drinking and ring entrance ceremonies make it a fascinating event to watch. There is also a bit of modern consumerism thrown in for good measure with commercial banners processed during breaks.  

It's an all-day event. Families rent a box and bring their picnics along. The fights start at 8:30am and go on till 6:30pm. Normal tickets at Tokyo's Ryogoku arena cost about £40 for the day. If you're prepared to start queuing at 5am, there are tickets available for about £12.