The ministry of transportation would not permit all the crew and extra buses (115 in total) on the freeway heading to the location each morning, fearing major gridlock on the Trans-Canada Highway, so each bus was strategically dispatched from several key points in the host city of Calgary every 90 seconds. This avoided traffic jams.
Only one injury occured during the course of filming all the battle scenes. A Japanese wrangler lost a thumb during the night shift, when his hand got caught in some rope attached to a horse. First aid was applied and the thumb was saved.
It took four months to film all the battle scenes for the film, each day using 500 crew, 80 wranglers, 95 Assistant Directors, seven full camera crews (two Japanese and five American), 40 tons of wardrobe, 3000 extras, 800 horses with riders.
The production bought 500 horses, as that was far cheaper than renting and the budget for feed for the horses alone was $1,000,000. After the movie's completion, the horses were auctioned off, with most selling for more than what was originally paid. The primary draw by buyers was these horses had gone through an extensive training period four months before filming began.
The scenes that show some of the samurai wearing armored sleeves on just their left arms are historically accurate. Many samurai archers wore this greatly simplified armor, to facilitate using the asymmetrical Japanese long bow.