Take a couple of cups of soy sauce, add 1 cup of sugar (and a bit of molasses if you want to, it gives some flavor but can be omitted). Add about a shot (1 oz. or so) of dry sherry. Heat gently until the sugar dissolves. Then add some grated ginger and garlic (about a tablespoon of each).
My quantities are approximate, rarely measure.
Usually am my lazy self and just use the store bought.
Soy sauce, sugar, garlic, minced ginger, a touch of worcestershire (not traditional but still good). This is my default marinade for fish, chicken, pork. I don't think I make mine as sweet as Aunt Dot's, but it can be done to your taste. I also use dark soy sauce available at my Asian market.
Equal parts soy and light brown sugar, and the following to taste: garlic powder, fresh grated ginger ( i dont like the powder for terriyaki), black pepper.
This is the marinade my father and I have both been using since I can remember, and it also a great base to add other flavors too. For example its very easy to add orange zest and a bit of fresh squeezed OJ to add orange flavors.
Thanks every one for the replies - I have not been online for a little while and apologise for not thanking you all earlier. It seems there are a few variations to teryaki sauce! I had a recipe from a magazine that I used over and over - but unfortunately seem to have lost it! It was similar to the recipes you have posted - brushed over thinly sliced chicken, sprinked with sesame seeds and grilled it was delicious. When I was in NYC recently, I had a cuban dish which was grilled salmon with a bbq sauce - with rice and black beans. Delicious! It did remind me of the teryaki sauce recipe I thought I had!
I will try the recipes suggested and let you know of the results! Thanks again!