In the words of NUX:

UKIYO-E CHORUS (NCH-4) is a mini chorus pedal with 3 different chorus models including ST Chorus, SCH-1, and CE-1. You can switch the models by tapping the tap switch. Old-school Analog Chorus has always been warm but it was hungry for dynamic completion.

NUX’s modern-tech DSP yields a perfect combination of both worlds: analog and digital. To achieve all of the UKIYO-E Chorus objectives, our engineers had to develop an algorithm that mimics the principles of BBD chips – the key component of Analog Chorus effects. UKIYO-E’s active low-frequency provides the Traditional Analog Chorus Tone discerning ears have come to expect in a true analog chorus pedal. Dynamic Tone and Noise-Elimination ability put UKIYO-E into a completely separate category from cheap analog pedals.

Quality-grade BBD chips in large mass have become incredibly rare, so this method is not practical for making an affordable analog chorus device.Using DSP technology, NUX is able to offer a mini-pedal with a contrasting array of chorus tones.