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!

Richard Lock

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”.

Peter Lowthian

Marlow, Buckinghamshire

• This is to thank Mrs Langham’s daughter for her great kindness and dedication, day and night-after-sleepless-night, to save that dear little baby hedgehog’s life and restore it to health, even though I am perfectly certain it has more than thanked her itself (Rescue me, 10 September). And to thank Mrs Langham, and you, good old Guardian, for telling us about it all. (Lovely, lovely photograph.)

Ann Hawker

Ham, Surrey

• Since the Mangan family seems to be open to offers (Letters, passim) and there’s a bid for Lucy, can I adopt her parents Richard and Christine? Lucy could visit us at Christmas.

Alec Sandison

Ottery St Mary, Devon

• In 1962 I hitched from Ostend to Copenhagen, staying in youth hostels. Does the YHA handbook, invaluable to me then, count as a backpacker guide(Letters, 10 September)?

Bill Ramsbottom

Derby

• Join the debate – email guardian.letters@theguardian.com

• Read more Guardian letters – click here to visit gu.com/letters

• Do you have a photo you’d like to share with Guardian readers? Click here to upload it and we’ll publish the best submissions in the letters spread of our print edition