Even though it's a little out of my way, on Route 246 between Ikejiri Ohashi and Sangenjaya, I've making the trip out to Kirakutei for years. The Japanese-style curry here is simply the best I've tasted anywhere.
My favourites are their basic beef curry as well as their 'mountain mushroom' curry. Every curry has a roux with a distinctly different flavour and you can select your level of spiciness. There's a large range of toppings and styles.
I highly recommend you try it out, but be warned that lunch and dinner are very popular. If you don't like waiting, off-peak times are best.
You can buy their curry in little packets as well as in a 'curry pan' (deep fried bread with curry inside) on the way out.
The blackboard will be sure to have some style of having Japanese curry that you haven't thought of yet...
Pickles and onions come everytime as soon as you sit down. I have to stop myself eating them before the curry arrives.
The basic beef curry. Just spoon a little drizzle on the rice and eat it bit by bit until it is finished, which is always too quickly ;)
A chicken 'sag' (based on spinach). Indian name - still pretty Japanese in its flavour