A friend of Kanji's took us clam-digging last month. I was expecting SAND and even planned to bring a bucket and spade for the kids to make sandcastles if they got sick of digging (though I forgot at the last minute to throw them in).
Good thing, as we went to this rock beach instead. Luckily I brought gumboots for all the kids! We met the friend at a homeware store, and Kanji went in to get some supplies - rubber shoes for himself, digging forks, gloves, a bucket and a small chair (!) in case he needed a wee sit-down. All recommended by the friend, who has done this before - on those rocks, there really isn't a place to park your bum!
The kids held up quite well really. They found crabs and shrimps and hermit crabs and oysters (apparently no good for eating) and other creatures among the rocks, and occasionally a clam. I think I got two, but I was the first to find one. The beach is practically fished out, it's sad, apparently you used to be able to come away with a bucket-ful.
Erica needed a nap, so I happily took off in the car with her, to get her to sleep. Amy and Lena took off with Kanji's friend's wife to go play at her house with her daughter, who is the same age.
Kanji persisted, and ended up getting about two supermarket trays' worth of clams, for the 500 yen fee we paid for access to the beach! He could have bought as many clams and skipped the digging, but it was all for the experience! We had clam soup and clams fried in butter and garlic the next night (we gave them a day soaking to get the sand out)