Himuroku is yet another extremely popular tonkotsu-gyokai tsukemen place in the greater Tokyo area. If your adventure is in venture capital, you should invest in a couple more shops along this line, the saturation isn't quite to it's breaking point yet. Better find somewhere out of reach of Tanashi station, as Himuroku is legitimate.
Always get an egg. Always get the medium or small size. Always check out any recommended special toppings, like their unique spice mix.
The custom, 4 flour blend noodles are as good as expected. Most of the ramen magazines and websites praise the noodles first and foremost, and they don't disappoint.
Excellent soup, though if you are venturing this far out of central Tokyo on the Seibu line for tsukemen, you probably want to stay on a few more minutes to go to Ganja in Kawagoe.
Tokyo, Nishi-Tokyo-shi, Tanashi 3-9-10
Closest station: Tanashi