I use them regularly being in Japan. I must be having a stack of at least fifty pens + refills. They are fairly cheap (~$2) and available everywhere. I made a lot of engineering notes with these pens.
One observation not mentioned in these discussions is that the ink tends to fade quite a bit over time. Its not just the heat. My rooms are temperature-controlled. But notes from a year ago for e.g are lighter & several alphabets show part erasure. Give or take a few years, they fade away almost completely. Personal observation but restricted to using the fine tips (0.38 & 0.4). Not sure if same problem happens in 0.5 & 0.7 too.
Japan government entities do not recommend using this pen when filling out any form or making any signature. The person in counter quickly tests the ink every time a form gets submitted.
One observation not mentioned in these discussions is that the ink tends to fade quite a bit over time. Its not just the heat. My rooms are temperature-controlled. But notes from a year ago for e.g are lighter & several alphabets show part erasure. Give or take a few years, they fade away almost completely. Personal observation but restricted to using the fine tips (0.38 & 0.4). Not sure if same problem happens in 0.5 & 0.7 too.
Japan government entities do not recommend using this pen when filling out any form or making any signature. The person in counter quickly tests the ink every time a form gets submitted.