The Japanese have many healthy foods e.g. natto. seaweed, tofu,....
Natto is from fermented soya bean & is a well known natural blood thinner. It's supposed to reduce cholesterol, blood clots, heart attacks, pulmonary embolisms and strokes. It's also said to prevent balding in men, Alzheimer's disease, osteoporosis and cancer.
If you don't like the taste you can get it as a supplement at a health store in capsules. For those taking aspirin as a blood thinner you should consider switching.