Fortunately, G5 senior designer Lee Jung-hoon was in a talkative mood. After some good-natured smartwatch ribbing — “Ah, you have my watch,” he said with a gleam in his eye upon noticing the LG Watch Urbane on my wrist and revealing what was on his. “I have the newer one!” — he was more than happy to explain how his team arrived at some of the phone’s more outlandish quirks.

It’s also probably good for LG that its biggest secrets are hard for inquiring journalists to stumble upon. But I had a reason to be there — I wanted to hear the story behind the G5, the company’s latest flagship phone and the talk of Mobile World Congress with its unorthodox modular design.

LG’s R&D campus in Seocho, on the southern edge of Seoul, is not the easiest place to get to. After multiple taxi drivers told me on a cold March morning that it was impossible to take me there from the nearest train station, I ended up walking along highways and side streets for 40 minutes before spotting the tall, glassy building with LG’s familiar pink logo. It’s a good thing I happen to like crisp morning air.

Sam Byford

The obvious place to start is with the phone’s construction, which sees LG move to a metal build on a major phone for the first time. But to hear Lee tell it, this isn’t about playing catch-up to the likes of Samsung, Apple, and, well, just about everyone else in the smartphone industry. It’s actually about removable batteries. "It doesn’t start with ‘we have to use metal, we have to use metal,’" he says. "We start with ‘what is more beneficial for the customer?’ So we didn’t want to lose the core benefit of changing batteries, but at the same time we wanted to make it different." That’s where the G5’s Friends concept came from; the phone lets you pop out the battery with a novel release mechanism, then either replace it with a freshly charged one or slot it into an attachable accessory that further augments the phone. "How about making something like a gun magazine?" "We were trying to make it more fun, so we thought about how we could make the experience of changing the battery interesting, not just pulling out the cover and the batteries," says Lee, fiddling with the pop-off battery cover of an LG V10 to exaggerate the action’s awkwardness. "Some of the advanced research is by designers, without thinking about structures or possibilities, just thinking ‘How about making something like a gun magazine?’ Just push a button and *chk* like that. When you do this, you feel like you’re doing something special." I ask Lee if he’s seen The Matrix, and he knows what I’m talking about right away — the famous Nokia 8110 with its spring-loaded slider. That’s the kind of experience that LG wanted to instill in the G5, giving the act of using the phone a more physical dimension. And that’s why it had to be made of metal. "So for this [design] we need some kind of strong structure. When we pull the battery out, there’s empty space." Lee says, pressing the G5’s rear panel to demonstrate its strength. "So with plastic, we can’t — we need harder materials, so we thought metal is one of the possibilities to make it thinner and stronger. That’s why we picked metal. So it all started from asking how we can make the phone fun and interesting for people."

Sam Byford

Are removable batteries that important to customers these days? "I think so," says Lee. I put it to him that almost every major phone manufacturer has stopped offering the feature. "Of course we want to expand the range of our customers, but at the same time we don’t want to lose the value we have for the [existing] customers," he replies. "Somebody who wants to have something very nice and metal-feeling [on the other hand], because we didn’t have that before — that’s one of the attractions that we want to expand our customers with." At this point, I should probably note that I am one of those potential customers who hasn’t ever really liked an LG phone. I’ve never been a fan of the company’s glossy plastic finishes, and the recent models’ rear-mounted volume buttons always struck me as being different for the sake of it. But I do like the G5. Even if you ignore its modular Friends, the phone itself has a neat, sensible design that’s received a lot of positive attention. The G5 has a neat, sensible design Those rear-mounted volume buttons are gone, by the way. "It’s all about the style," says Lee, whose team was preoccupied with accommodating the G5’s larger dual-lens camera module, and ultimately decided that volume keys were better placed elsewhere because the function can also be accessed through the screen. "Because of the size it’d be a bit busier here. We thought that what’s core for the back keys is the ability to turn the phone on when you first hold it up, so we prioritized the fingerprint scanner and power button. At the same time, we could make the back of the phone simpler and nicer-feeling." That approach extended to eliminating the phone’s antenna lines through a process that LG calls "microdizing." The G5 went through multiple design iterations, some of which I saw in prototype form (pictured below), before LG hit on the technique; Lee calls it the company’s "hidden recipe" and won’t explain exactly how it works. One line that does appear is a slightly sharp edge — LG calls it "shiny cut" — that runs around the phone’s rear and improves its grip despite the fairly large 5.3-inch screen. It’s a neat twist on the curved unibody design that makes the G5 easier to hold than something like an iPhone 6S Plus. The G5’s glass also has an attractive curve toward the top of the display, a feature adapted from some of LG’s mid-range phones. Lee says he wanted to give the phone a three-dimensional element and described the effect as "very subtle, very sophisticated, but outstanding" — as in the kind of thing that would make the G5 stand out among other phones in stores.

Sam Byford

But the biggest standout feature, of course, is the Friends modules. While Lee says the idea came from dreaming up a better way to switch batteries, LG is also selling a camera grip that further extends battery life and a DAC module co-developed with Bang & Olufsen that turns the G5 into a high-end audio player. While I’m not convinced that these will be major sellers or a genuine point of attraction for the phone — though, anecdotally, I did see a lot of people switching batteries on the subway during my time in Seoul — they will mark the first time a major phone manufacturer has succeeded in getting a modular product to market. (Unless you count the Palm OS-based Handspring Visor.) LG has been holding developer events in an attempt to gain more third-party support for the concept, suggesting it’s not a gimmick to be abandoned with future flagship phones. "We are not going to stop with this." I wanted to ask Lee about this, and whether these modules were likely to be forward-compatible with upcoming LG phones — after all, their design is so tightly bound to the G5 that it could constrict the G6’s form. "We have to evolve, we have to improve. We are not going to stop with this," he said, comparing the Friends modules to cases that customers replace with new phones. [LG representatives later followed up to clarify that the company’s official stance is that it will stick with the modular design in the future.] Whatever the future of Friends, the G5 looks to be LG’s best phone yet even if you never pop the battery out. We’ll need to give the phone a full review to see how well it holds up next to Samsung’s impressive Galaxy S7 and S7 Edge, but my early impression is that the company’s design approach manages to strike an attractive mix between invention and restraint. That matches what my colleague, Vlad Savov, thought upon spending time with the G5 at Mobile World Congress, writing that "it took a set of quirky accessories to help [LG] focus that innovation into a single, outstanding smartphone." I have my doubts that it’ll be enough to help the company vanquish its long-standing rivals, but it’s an encouraging new direction.