I didn't know you could buy direct from Shimano.

I usually just keep an eye on all the online vendors that I buy from and when they show up as in stock, put in your order before it's out of stock.

This summer I had to watch for an eleven speed chain, I wanted either KMC or Shimano. I think I checked five different vendors daily for a week maybe two before it was in stock at one and I grabbed it. The next day they were out of stock again. At this particular vendor if I'd waited for the in stock notice in my email to check them, then I would have missed it because they were out of stock again by the time the email made it to me.