“Window or door screen repair, window pane replacement…” As the familiar soundscape of common people’s lives rises and falls around us, memories in the margins of the city are awakened one by one.

On the shortlist of TIDF’s Taiwanese Competition this year, Flow is developed from the ideas director SU Ming-yen had, a few years ago, for a short film inspired by the Liugongjun Canal murder case. The previous script was revised at the invitation of Ryan CHENG, the executive producer of short films for PTS’ Viewpoint documentary programme, and the focus of the film was shifted to the area around Toad Mountain, along the Liugongjun canal system. Beginning with a drying-up ditch and ending with raindrops trickling into the canal, the film portrays the lives of various elders, explores their hidden stories and the emotions and memories filling the cracks of the city.

Sound is a crucial part of this film. How did you come to work on the soundtrack with Thomas Foguenne? And what are your thoughts on incorporating natural sounds?

I invited Thomas Foguenne to work on the soundtrack through a friend of mine. There are concepts in the film that are more abstract and speak to one’s sensibility, which he could grasp really well. Our communication was quite smooth. Once I wanted him to try a more extrovert style, which is actually the opposite of what this film is like. But eventually I referenced the soundtrack of a Thai film, Last Life in the Universe (2003). Such psychedelic style is much more suitable for Flow.

As for the sampling of natural sound, I pretty much used whatever I collected randomly, except the “window screen repair” advertisement, which was from a tape one of the elders in the film gave me. He used to repair window screens for a living. I like to pay attention to the space and sound in a city and this film is about memory, so I’ve incorporated the sound of the advertisement, which gets people into the reminiscing mood easily because everyone is quite familiar with it.

The backgrounds of the filmed subjects are not revealed through any dialogue, interview or text in the film. Why did you choose to employ such an abstract approach?

During the process of filming, I simply observed and followed their daily lives. I didn’t ask them to do anything. Those elderly ladies told me stories about the area around the canal system. I wanted to include some of them originally, but I felt it might disrupt the sensibility of the film. So, eventually, I chose not to.

I think, for some extent, shooting a documentary is to reveal the embarrassment of the filmed subjects on screen. Being an artist or film director can bring little change to society. For example, the visually impaired subject in my other film Listen, Darling (2014) still has to work as a street performer while I’m here being interviewed. Making a documentary is to show the audience other people’s lives in a short period of time. I don’t think I have found the way to strike the right balance yet. I was simply convinced by PTS producer WANG Pai-zhang and executive producer Ryan CHENG to try again at finding other ways to balance the situation when making Flow.

Is there any symbolic connection between the imagery of a subterranean river and the filmed subjects? How did you bring the materials together in the editing process?

I usually said there’s no connection when I was asked about this, but we did have the intention to make some. The imagery of a subterranean river is connected to the filmed subjects through the concept of memory. Space and the human body are like containers. How we place memory inside them is similar to how water flows and how blood flows. They are interconnected.

The way I usually work is to start with “points”. I think of many points and then I try to link them together. I believe a film should have some kind of structure. When I edit a film, I have a preconceived structure and context in mind. When I got stuck while editing this film, I went through the footage on my phone and found a piece where an elderly lady burns joss paper for her late husband, which could work with the previous scene where she bumps into her old neighbours who have come back for the anniversary of their father’s death. What’s more, I accidentally filmed an elderly man throwing joss paper onto the surface of the canal. At that moment, I realised that all these scenes were about death. So I followed this theme and completed the editing in one go.

Imagery related to water, such as IV drip, steam and river, is frequently used in this film, which is also titled Flow. Why did you choose water as the key element of the film?

I chose to start with the idea of a subterranean river because the Liugongjun canal system was built mostly underground. I tend to start with space when I make a film, so I wanted to see the size of the area the canal system covered. The element of water was actually introduced later. I normally just immerse myself in the space around me after filming begins and not insist on capturing certain things. These elements were put together naturally during the editing process in post-production, which is very different from how a fiction film is made.

Your grandmother appeared in some of your previous films as well as this one. What role did your grandmother play in your filmmaking career?

I thought I should learn how to make films by filming the people around me, so my graduation work Daylight Developing (2011) was shot in my hometown Changhua, where my grandma lived alone. By making a film about home, I hoped to keep her company and to learn more about film, myself and my family. I have another film assignment titled Grandma (2008). Together with Daylight Developing and Flow, they form a trilogy about my grandma.