He looks just a regular Chasid among the strictly Orthodox legions of north London's Stamford Hill: his kippah is black velvet, he wears peyot and he is the product of Yiddish-speaking school and yeshivah.
But Pen Tivokeish - to give him his pen-name - harbours a secret. He is part of a religious underworld, the author of a blog where he records his true feelings as a Charedi man who does not believe in God.
For a year now, this family man in his 30s has been quietly posting online, writing about the books he has read, or the programmes he may have watched - on computer, he has no TV at home - or drawing vignettes of the Chasidic lifestyle to which he still remains attached. His blog, called Penned-In - a pun on both his own sense of confinement and his writing - has proved an outlet for "stuff I probably can't say in any other settings", he explained.
His journey from yeshivah boy to blogger began only by chance several years ago when he was in Israel to visit a prominent Chasidic Rebbe. "A friend of mine mentioned that he was going to an Aish seminar, which gives you a crash course in learning in how to answer questions about Judaism and the historicity of our stories and reconciling science and the Creationist view," he recalled.
"I was a little bit reluctant. In our circles, it is generally thought emunah pshutah [simple faith] is the way to go and one is not really supposed to question the way at all because that can ultimately lead to heresy.
"However, I thought I won't be influenced because my faith was to me quite untouchable. I thought it would be nice to be able to answer questions when you are sitting on a plane and people tend to ask you what is your take on evolution. Sometimes it is quite awkward not being able to answer… So I went."
The seminar impressed him, offering ideas on how evolution can be squared with Genesis and evidence for the Exodus. When he got home, he decided to follow up what he had heard, looking up websites on his computer. But the more he began to scour the internet, the more the Aish arguments - and eventually his faith - began to unravel.
"For about two or three years I was involved in this struggle, nobody knew about it, not a single person," he said. "And I still considered myself a very strong believer throughout this time until it reached a tipping point."
One Friday night, during the Sabbath eve service, around four years ago, he said, "I remember standing in the corner of the steibl… and they were singing. It just dawned me - it was something of an epiphanaic moment for me, when I realised 'Hey, you just don't believe, and it's ok not to believe, it's just what you are, nobody can blame you for it.'"
There was "no real reason to believe in a Deity", he felt, and the Bible was not true. "I generally don't like the term atheist, because it has strong in-your-face connotations, it is battling against something that doesn't exist," he said. "So I prefer using the more docile term of agnostic."
Outwardly, he has maintained his strictly Orthodox demeanour. "Even if the Chasidishe way of life has some really debilitating aspect to it, it is still quite beautiful in a way," he said. "Judaism is my culture, it's the culture I love, and the culture I was brought up in." Nevertheless, he felt isolated and even sad. "I didn't really have anybody who could relate to my state of mind and I didn't really have anybody to talk to," he said.
Until he reached for the keyboard. "When everyone around you believes God to exist, to be all-punishing, you tend to behave as if God might actually punish you for a long time," he said. "It takes a long time till you are comfortable transgressing the rules. Starting a blog is actually the ultimate transgression because you are actually proselytising against God…
"It's not something I considered or thought about doing for a while. One day I created a blog and came out with my pen name, and I just started writing and people responded quite well."
His name Pen Tivokeish is a play on a phrase from Deuteronomy, "lest you be ensnared" (his true identity remains concealed). The blog introduced him to an online community of like-minded people, mostly in the States. "The blog helped insofar as I developed a network of friends and I didn't feel as isolated at all," he said. "It helped my frame of mind." He has readers in Stamford Hill, although he does not know how many.
His biggest worry is the education of his children. "Because my boys are in Israel in yeshivah, they are not getting secular education and that's something that disturbs me a great deal because that makes me part of the system, part of the problem insofar as the economic unviability of the system [goes]. It's a problem because there is not much I can do… You can't be in the system and send your children to a more secular school, or even to a modern Orthodox type of school - you are either in it or out of it, you can't have it both ways."
Lately, he has also become contributor to a new American website called Unpious, an online forum that describes itself as "for those whose roots are in the Chasidic world but have left it in body or spirit".
But do not take his, or the Unpious, blog as a revolutionary crack in the yeshivah walls. He believes that electronic communication has actually strengthened Charedi society, building its disparate groups globally into a "megacommunity". Despite rabbinical fulminations against the internet, he said: "Although unrealised, it's probably more a force for construction than destruction. But I might be completely wrong."