May children play with a writing board, which is has a plastic sheet which when lifted erases the letters?

            The Mishna in Shabbos 104b specifies the foundation for the melacha of ëåúá – writing. The two main fundamentals of the melacha are that one write with long-lasting ink and that the letters are written on a durable surface. These two features coupled with the required amount of letters written, obligate the writer to bring a korban for violating an issur d’oraisso – a biblical commandment.

The Mishna says that were one to write with say fruit juice on a durable surface or with ink on a non-durable surface, one would be absolved of an issur d’oraisso.  Nevertheless, mid’rabanan one is prohibited from doing so.

We must add that it is not imperative that ink be used to be liable for the issur d’oraisso because engraving or etching is equal to writing with ink, provided that it is done on a surface which leaves an imprint, thus fulfilling two of the requisites of the melacha. [1]

Based on the above, a delegation from ‘Hachovesh’, (the emergency service of Har Nof, Yerushalayim) approached Rav Shlomo Zalman Auerbach ztz”l and asked whether the writing board with the plastic sheet could be used on Shabbos for writing with by the emergency dispatcher. (They were obviously aware that normally it would at least be ossur mid’rabanan to use such a board, however the question was whether it was better than writing with ink on paper).

Rav Shlomo Zalman answered that one has not gained anything by writing on such a board, because although one normally erases everything etched onto the board, but until it is erased it is considered permanent writing and therefore a d’oraisso.

Therefore, to answer the question, writing or drawing on such a board on Shabbos is ossur mid’oraisso.

            Is one permitted to draw shapes on a frosted window?

            Drawing shapes or writing on a frosted window is ossur mid’rabanan on Shabbos. Although the writing is not permanent, nevertheless Chazal prohibited writing or drawing that is non-permanent. Accordingly therefore, one may not write by tracing one’s finger in sand, or write in a film of liquid on a table, or draw a picture in the dust on a table. [2]

            What about writing in the air?

            There is no issur to imaginarily draw shapes or write letters in the air because one is not leaving a mark anywhere. [3] For the same reason one may trace letters with a ‘dry’ finger on the table or on paper because one is not leaving an impression.

            Is there a problem eating cookies or cake with letters formed on them?

            The Mordechai [4] in the 7^th perek of Shabbos cites a question posed to the Maharam. The custom was that on Yom Tov (probably Shavuos) children would eat cake with letters formed on the cake and the problem is that they were erasing the letters. The Maharam answered that although it is not an issur d’oraisso because for erasing to be an issur d’oraisso it must be with intention of replacing the erasure or for some other positive benefit. Notwithstanding, it is ossur mid’rabanan, but since it involves children and adults are not handing them an issur, [5] it is permitted for them to eat the cake. The Rama [6] quotes this as the halacha.

The Mishna Berura [7] however quotes the Nodah Biyhuda [8] who argues and is lenient. He says that the case of the Maharam was where the writing was purposely intended to be eaten by the children as a ñâåìä – a spiritual enhancement to Torah (on Shavuos) and therefore he only permitted it for children, but in regular cases everyone may eat such cake.

The Mishna Berura rules that one may rely on the lenient opinion when biting into the letter with one’s teeth, but he does not permit cutting the letters.

The Mishna Berura [9] adds that the entire debate revolves around letters formed on cake or cookies, such as icing, but when the writing is of the same substance as the cookie, i.e. it is etched into the cookie, there is no problem to break or cut the cookie. [10]

            May one open a book with letters or words written on the edges of the pages? (The words are seen when the book is closed).

            In his respona the Rama addressed what seemed to be a common issue. It was customary to decorate a sefer with writing on the edges of the pages and hence the question was whether it is permitted to open such a book, thereby erasing letters, and shutting the book, thereby writing and reforming letters.

The Rama [11] and many others permitted this, saying that it is similar to the opening and the shutting of a door. Just as we do not say that opening or shutting a door is Boneh and Soter (construction and dismantling of the building) so too we do not say that one is writing or erasing when opening and shutting such a book because it is ‘created’ to do so.

On the other hand the Levush and the M”A held that one should not use such a book on Shabbos. [12]

The M”B states that the custom is in accordance with the Rama, but if possible to use another book without edge printing, one should use the alternative book. He concludes that one should definitely avoid printing such seforim in order to comply with all the poskim. [13]

            Are there any cases where erasing will be beneficial and constructive and thus ossur mid’oraisso?

            Besides the obvious case of erasing in order to be able to write in the place of the erroneous letters, there is another case. The P’ri Megadim writes [14] that erasing an IOU note that has been paid would be an issur d’oraisso, because it is beneficial. Usually erasing is destructive unless done with the intention of writing in its place, but in this case the erasure is beneficial on its own.