17:00 UTC
18:00 CET   (Amsterdam, Berlin, Paris, Rome, …),
17:00 GMT   (London),
12:00 EST   (US East Coast, Boston, New York, …),
09:00 PST   (US West Coast, San Francisco, Seattle …).

Half an hour before the workshop starts, the Zoom session will open for an informal gathering, the greeting / introduction of new participants as well as meeting of old friends, resolving any technical problems, social contacts in the slide rule collector community.

The deadline for the registration for IW-6 (see below)

Deadline for the submission of new "unknowns" is November 4, 2026.

Save the date: The next workshop IW-7 is scheduled for March 7, 2027.

The workshop uses the WWW based Zoom online conference system. All you need to participate is a web browser and an Internet connection; there is no need to install any special software on your computer. Registered participants will receive the URL for the workshop including its access code the day before the event.

As a compensation for this lost opportunity to see, inspect items in detail, to discuss them, and ultimately find answers to unknown properties, like manufacturer / distributor, purpose, usage, "strange" scales and special features, date / period of production, and more such aspects, a new series of International online Workshops was created, called IW followed by a sequence number. It started with IW-1 in February 2025, and IW-6 in November 2026 is the latest. The workshop frequency is about three to four times per year.

The format of two hours with a little break turned out to be just right for such a lively meeting with its very brief initial presentation and the discussion of items with unknown properties. The focus on a particular item and its associated mystery aspect(s) helped significantly to get results within the given time frame. There are however issues not bound to a specific slide rule, but to more general features, like the type of wood or other material used, questions of dating specimen, ways to find out this or that about slide rules. A second class of themes are the experiences of the participants in handling their collection, for instance repairs, storage, replacement for missing boxes / sleeves for storage, tagging and keeping inventories. There have been small discussions between a couple of participants, and we plan to have some part like up to half an hour of the workshop for the exchange of experiences of the participants. This is to be discussed for trying such exchanges at further workshops. Please supply your feedback; we expect that the characteristic and format of the workshop will evolve over time.

There is no need to be a member of any of the organizations running or backing the event. You do not have to have a large collection; our rule of thumb is that three items of something just mark the begin of a collection!

Finally, participation is free of charge !

There are only two requirements to joint IW-6:   (a) You must be able to connect via a web browser to the zoom meeting. Although it is in principle possible to watch the workshop on a smartphone, it is not advisable, as you will want to inspect the items of discussion on a sufficiently large screen for your inspection of details. For active participation you will need a webcam. It is a standard feature of all notebooks for quite some time. For a classical PC, you will need a separate web camera; not a big expense for reasonable quality.   (b) You must register to participate. Details for that further below.

There you find the list of all mysteries, both open, handled (not for all we do find a solution), and solved. That includes a picture and a set of questions for each item. If you click on the picture or the item title, you can see more pictures, answers, suggestions, remarks and more from participants, often already before the item is handled in a workshop session.

(a) You have a slide rule with something you do not understand or wish to know more about. Some mystery, for which you want an answer.
In this case, look at the list of mysteries on the workshop's web page, take a photo or several, formulate your question(s) taking current items of the list as a model and send them to Andries at info@rekeninstrumenten.nl for inclusion in the problem list.

(b) For more general questions, where you would like to have some feedback from the assembled expertise of the participants, contact the organizers if / how / when to raise the subject. On the one hand, there is a good chance that they already can answer your question, on the hand we will improvise a way to bring it up somehow at the workshop — see further up on the character of the workshop and its evolution.

Email to both karl.kleine@eah-jena.de and info@rekeninstrumenten.nl with the subject line Registration IW-6. State your wish to register for the workshop in the body of your email, providing your full name, your email address, and your location (place and country / state). If you are a new participant in the workshop series, please mention that also.

In your registration and when joining the zoom session, use your full name. No acronym, no nickname and no fantasy name, please — it's a workshop, not a Halloween party.

You will get the URL to join the workshop a day or two before the event.

The workshop committee consists of Chris Hakkaart (KRING president), Andries de Man (workshop web page, and more), Karl Kleine (zoom meeting coordinator), and Leo van der Lucht.