I drew these guys with a Pilot Custom 823 FA and Platinum Carbon Black ink. The FA nib has a good drawing width on watercolor paper - one of my favorites. It's a soft nib but I don't use the line variation, just some nice shock absorption with each downstroke. The Carbon Black ink is out-of-this-world good, though being pigmented I fear keeping it in too many pens.
This was drawn with a Japanese fountain pen, Japanese ink, and painted with Japanese watercolor. To be specific - I used Holbein watercolor and Platinum Carbon Black in a Pilot Falcon. This trio is perfect for me.
