Re the “arbitrary figure” of 10,000 steps (G2, 3 September), the number has significance in Japanese culture – 10,000 in Japanese is ichiman, a unit in Japanese mathematics. The standard large currency note is 10,000 yen, the number of years wished at someone’s birthday is 10,000 – and when, more than 50 years ago, I asked my Japanese judo sensei how many times I should repeat any move to perfect it, he replied (in English): “Aaaah – 10,000 times!” So, not surprisingly when the ancestor of Fitbits was invented in Japan to count paces, the number to aim at was ichiman. Any similarly large number will no doubt produce much the same effect. Keep walking!
Westmount, Quebec, Canada
• Dining on roadkill depends on one’s constitution (Report, 3 September). In Heavy Weather, by PG Wodehouse, Galahad Threepwood tells the tale of Eustace and Freddie Potts, who were served a casserole of what turned out to be hedgehog. The teetotal Eustace fell violently ill, whereas Freddie, “his system having been healthily pickled in alcohol, throve on the dish and finished it up cold the next day”.