Multiple reentry on a six month landing visa?

Hello, I hope this is the correct forum to post this question in. I am considering moving to Tokyo for a six month stint early next year. I won't be working in Japan, as I work online, so I intend to just come in on a tourist/landing visa (UK passport).
My query is whether anyone has any experience in coming in and out of Japan multiple times on a tourist/landing visa? The reason I ask is that I also work for a courier company and they have work out of Tokyo. I really enjoy the courier trips so I'd like to keep doing that too. Will this raise problems with immigration? If anyone has any insight into this it would be much appreciated.

Thanks in advance.

what's this 6 month landing visa? Have you done any actual research on this?
Japan travel advice - GOV.UK

As an American, I can enter Japan for up to 90 days at a time, and 180 days for the calendar year. That means I can legally go twice for 90 days, or 3 times for 60 days apiece, etc. Assuming it's the same for UK passport holders, every time you leave and come back, you're resetting your 90-day countdown for that trip while the 180 day clock runs down in the background. That said, you aren't supposed to work without the proper visa, and coming and going a lot will raise eyebrows and could cause you trouble, especially if you're traveling for work. You don't get one visa and re-enter on it, every time you leave and come back you're getting a new landing visa and will be under immigration's scrutiny.

Also, airlines will often require proof of a return or ongoing ticket before letting you even board. I've been flying standby and when I first came this year, I had to purchase a return ticket to get my boarding pass. When I came back to Japan after a brief visit to Korea, I had a better idea of when I'd be going home so I bought the ticket I intend to use in advance. When asked, I tried telling the agent at the check-in counter I was flying standby, to gauge their reaction. They immediately started looking around and getting fidgety and I could sense it would be a hassle, so I produced the confirmation e-mail and sailed right through.

At the very least, the cost of traveling by the seat of your pants is the price of a fully-refundable flight to some other country.

I thought Brits could come for 2 x 90 days without a visa. Confirm with your local embassy/consulate.

As for down the road doing courier visits, people from the Asia Pacific region and the Latin American region, Russia and New Independent States (ex-USSR) on a multiple entry visa can do that.

Your profile says you are "from Taipei", so presumably you are either a Brit living there, or someone with 2 passports living there. Either way, you are too old for the working holiday visa.

Thank you both for your reply. My understanding is that I can get 2 x 90 landing visa (or a 90 day landing visa extendable to 180 days) as a Brit.
It seems that Japan is a little stricter than Taiwan on this front, as on paper I would have the same entitlement here but in practice many people simply nip out of the country and then restart a new landing visa in the same calendar year. From your replies it seems that this is not the case in Japan.
I don't have to keep on doing the courier work, I can just take a break from it if it seems like it would be an issue with immigration. Probably makes sense to keep my head down anyway.
And yes, I'm not eligible for the working holiday visa. To be honest I am happier to retain the flexibility of working online so I can disappear off to see a bit of the country.