Posts on y15a

My AI-accelerated software development journey

Wed, 13 May 2026 12:30:00 +0000

2023 Used ChatGPT extensively for research and questions.

2024 Continues.

2025 Q1 Started using Cline on VS Code and Cursor.

2025 Q2 Claude Code lands. New apps and components start being built by Claude.

2025 Q4 Opus 4.5 lands, feels we have something that truly rivals a senior human programmer.

2026 Q1 Built a multi-agent workflow using GitHub as the collaborative & shared memory tool.

What a year it has been.

The Entropy of Life and the Serenity of Enlightenment

Fri, 27 Sep 2024 23:33:17 +0900

For much of history, humans have sought to define the purpose of life. Early views were often centred around survival, reproduction, and protection of those we care for. As our understanding deepened, life came to be seen as part of a broader, interconnected system — a web of organisms and exchange of energy. Life, in this expanded view, is not merely about individual existence but about sustaining and participating in the path to equilibrium.

A Measure of Code's Value

Fri, 27 Sep 2024 11:55:55 +0900

As a software engineer and startup founder, I often ask: what makes software valuable?

Code has no intrinsic value - its worth is entirely contextual. For instance, x = a + b isn’t inherently more valuable than x = a * b.

However, we can measure its extrinsic value: how often the software runs. Or, put more formally:

Number of times the software is run per unit time

By this measure, Windows is far more valuable than macOS. And the Linux kernel, which powers the majority of web servers and every single Android device, might be the most valuable of all.

Essential apps on my Mac: 2024

Sat, 18 May 2024 12:03:35 +0000

I rely on my MacBook Pro for both life and work. As such, I have a wide range of apps installed for business administration, software development, design, photography, and everything in between. Here’s a list of the apps I use heavily, regardless of the project I’m working on at the moment.

Alfred 5

Alfred 5 is a powerful Spotlight replacement for Mac. It offers file search, shortcuts, dictionary, and recently, AI integration. The best thing about Alfred is its customisability. Some of the workflows I use the most are:

Zero-step scaling with an office-less organisation

Fri, 27 Oct 2023 03:11:30 +0000

As part of our ongoing hiring effort, we have received numerous applications from individuals who lack prior experience with remote work. In this article, I’m hoping to provide extra context around our decision to become an office-less organisation.

Joyz Inc. has implemented an office-less management system that embraces the distributed/work-from-home style of work company-wide.

The 2020 pandemic started it all

For Joyz, like many other companies, the direct impetus for moving to office-less management was the outbreak of the COVID-19.

My first 50 days of being the lead software engineer (again)

Thu, 21 Sep 2023 06:56:50 +0000

Recent departures at our company led to a lack of technical leadership, especially in the infra/backend.

We had two choices. One is to scramble to hire a tech lead. Two is for me to assume the role temporarily while simultaneously functioning as the CEO.

We went for the second option.

This may seem like a red flag to some people. It is not ideal. Equally, I wasn’t ready to throw someone into a job where they faced technical obstacles while understanding the users, the team, and the codebase. I was not confident enough to complete the hire in a month.

About that iPhone announcement

Wed, 13 Sep 2023 08:23:28 +0000

USB-C. It’s about time, but for models with A16, it’s still running USB 2.0. Probably due to the lack of USB 3.0 controller in the chipset. Not that anyone would be troubled by the sub-GB/s bandwidth in this wireless age, but for an industry flagship product to have technology THIS old is kind of comical.

With the weaker Yen, the new iPhone 15 Pro base model costs about the same as a month’s rent for my house. It accommodates a family of four, and a dog, comes with a parking space, located in a town that’s 30 minutes away from Tokyo by train.

MacBook Pro 14-inch, 2nd gen

Sun, 16 Jul 2023 05:17:13 +0000

I’ve been with it for over a month now. This is easily the best computer I’ve ever owned.

I don’t have to go over the performance and battery life offered by Apple Silicon, as its superiority is apparent in spec sheets and rave reviews. Still, this thing handles pretty much everything I throw at it.

As a technical startup CEO, I split my time between People, Capital, Product and Administration. MacBook Pro will keep up with it for an entire day. Video conferencing for hours? No problem. Opening a large spreadsheet for financial modelling? Easy. Running virtualised Linux servers through Docker for Mac? It’s faster than running it bare metal on an Intel laptop.

Intro to Motion: the app that changed my productivity formula

Fri, 04 Nov 2022 09:40:51 +0000

I have been using an app called Motion for a good while now and it has completely changed the way I think about my work and productivity. At the same time, I always thought their marketing and the founder’s sale pitch were a bit bizarre (sorry), potentially putting off some users who would otherwise be a great fit. So, I’m taking a shot at explaining what’s revolutionary about the product. I’m in no way affiliated with the company. I’m paying to use the product.

Scaling EdTech: A Business Development Perspective

Tue, 01 Nov 2022 00:26:49 +0000

For institutional EdTech businesses to scale, business development must revolve around proving efficacy as a large-scale intervention. The key here is that any government-led regional instalment of EdTech products will be a policy decision and not a purely pedagogical one.

One reason pedagogy seems very fragmented and teaching methods differ greatly from teacher to teacher is in academia’s pursuit of novelty — particularly in learning/teaching methodology. When your goal is inventing a new method that is more effective than the baseline method, your research project will need to ensure that the methodology is strictly enforced. For that, you likely need someone who’s already very invested in understanding the methodology — a colleague, or even the very author of the research project. This level of methodological enforcement is very difficult to achieve in the real world, unless you have the budget for extensive training as well as in-term audit. It is also likely that teachers participating in the study exhibit a bias in terms of their general passion in improving their teaching. Simply put, it’s all far too optimistic.

Learning as a function of experience, talent and dream

Tue, 29 Mar 2022 22:03:33 +0000

As a CEO of an EdTech company and a father of two toddlers, I’ve put a lot of thought into what makes people learn new things and develop to be the person they aspire to be. This isn’t limited to learning that typically happens in schools. Personal growth and development are fundamental requirements for a thriving organisation.

I’ve come to observe in my professional career that the amount of learning one makes out of a particular experience differs greatly by person. In sports, for example, the same amount of training can yield drastically different skill levels, depending on what people typically call ‘a knack’ or ‘a talent’. The same phenomenon can be observed in virtually anything. Great programmers acquire new concepts quickly and apply them to their work right away. Great marketers generate customer insight like no one else. Sometimes you’re left in awe of how easily mathematicians spot patterns in a seemingly unrelated set of observations. The list goes on.

Interview by AI Pro Blog

Fri, 11 Oct 2019 12:32:52 +0000

Nicely covered. Interview in conjunction with Google’s LuanchPad Accelerator Tokyo, which we’ve been selected for Batch One.

Joint research with University of Tokyo announced.

Wed, 03 Oct 2018 04:30:03 +0000

Joyz, Inc. (Head office: Shinagawa-ku, Tokyo, Japan; CEO: Yoshiyuki Kakihara; hereinafter referred to as Joyz) announces that it has started joint research with the Saruwatari-Koyama Laboratory, Graduate School of Information Science and Technology, The University of Tokyo, on the application of speech synthesis technology to language acquisition. In this joint research, Joyz will work with Assistant Professor Shinnosuke Takamichi (hereafter, Assistant Professor Takamichi) in Saruwatari Laboratory, Department of Systems Information Science, Graduate School of Information Science and Technology, The University of Tokyo, to develop effective foreign language acquisition methods utilising learning history and speech data owned by Joyz, in an industry-academia collaboration system.

DjangoCongress JP 2018

Fri, 01 Jun 2018 09:00:00 +0000

I gave a talk at DjangoCongress JP 2018 named “Django in the age of AI - the Good, the Bad and the Ugly”.

I have been somewhat distant from the local Python community since I helped run PyCon JP 2014 as a publicity team member. I hope my talk was interesting enough.

JAWS DAYS 2018

Thu, 10 May 2018 10:00:00 +0000

AI英会話アプリ「TerraTalk」のHeroku＋AWS活用法

I gave a talk at an AWS user conference.

I spoke about the technical challenges of AI English learning app TerraTalk, the back-end configuration and our agility-first architecture.

Thank you to everyone involved for the opportunity!