I have been wanting to make walnut boats for Goblin since I saw them on various Waldorf inspired blogs, but I haven't been able to find walnuts in shells anywhere. Then last week I stumbled on them at my local fruits stall. Just in time for Valentines day.
I bought a big bag because I realised that it was going to be hard to split them accurately and I might have quite a few that failed. To split them I shoved a knife into the cross at the base of the walnut. Then tapped it deep into the nut and twisted. About 50% split straight down the middle.