It can be assumed that preschool teachers will read renrakucho notebooks in the morning, which makes "good morning" an appropriate opening greeting.
It is not necessary to write an opening greeting when replying to inquiries or similar messages from the preschool.
The Japanese phrases above are shown in increasingly formal order. If you have just entered the preschool, if you are writing or speaking to a teacher who is significantly older than you, or if you are approaching a teacher with a concern or a request, you may wish to use one of the more formal phrases.
However, always using formal phrases makes it difficult to develop a sense of friendly familiarity with others. For this reason, you may choose to use casual greetings such as 「おはようございます」(ohayo gozaimasu, or "good morning") on a daily basis, and save more formal phrases such as 「お世話様です」(osewa-sama desu) or 「お世話になっています」(osewa ni natte imasu) for times when you wish to talk about a concern, make a request, or express your gratitude.
This phrase is used to imply that you are always thankful for the things that are done for you and your child. It may be used as an opening greeting at the beginning of a written message.
These phrases are used to thank teachers for their concern, or for worrying about your child.
This phrase may be used to thank teachers for having helped you solve a problem, for having taken your child to a medical facility, or for having otherwise gone out of their way to help you in some matter.
This phrase is used to express appreciation to teachers for everything they have done. It conveys a sense of being both indebted and grateful to the teachers.
This phrase is used to thank teachers for everything they have done, and also to express appreciation for the energy and effort they have expended.
「ご苦労様でした」(gokurosama deshita) has a similar meaning but may at times sound condescending and even rude, so it is probably best to avoid using it.
This phrase is used to express gratitude when your child brings food back home from school, or when your child is treated to food or a meal at the school.
These phrases are used to thank teachers for talking about things with you during discussions or meetings. 「ありがとうございます」(arigato gozaimasu) would convey a stronger sense of gratitude.
「すみません」(sumimasen) is appropriate for everyday use. The more formal「申し訳ありません」(moshiwake arimasen) is used to apologize to the school or teachers for having caused trouble or inconvenience, and it is overly polite for casual daily use.
In casual daily communications, you may omit 「よろしくお願いします」(yoroshiku onegai shimasu). Japanese parents often use yoroshiku onegai shimasu as a closing phrase at the end of written messages.
Yoroshiku onegai shimasu ("thank you") or sumimasen ga yoroshiku onegai shimasu ("I'm sorry, but thank you") are used when making requests of teachers, while 「お手数ですが、よろしくお願いします」(otesu desu ga, yoroshiku onegai shimasu, or "I apologize for troubling you, but thank you") is used to acknowledge that your request will create more work for the teacher.
The above phrases are appropriate for use when you have a specific request to make of a teacher. If, on the other hand, you do not have a specific request (for example, when you explain your child's situation and ask the teacher to take appropriate action depending on what happens at school), it is better to use requests like 「すみませんが、よろしくお願いします」(sumimasen ga yoroshiku onegai shimasu, or "I'm sorry, but thank you") or 「お手数をおかけしますが、よろしくお願いします」(otesu o okake shimasu ga yoroshiku onegai shimasu, or "I'm sorry to trouble you, but thank you"), which are more open-ended ways to make requests or ask for cooperation.
It is customary to sign messages with your family name. You may also use a personal seal (called an inkan or hanko) to stamp your family name instead of writing it.
You may also refer to yourself as "(child's name)'s mother" or "(child's name)'s father". Japanese parents usually do not use the -kun (for boys) or -chan (for girls) suffix with their own child's name.
If your child's renrakucho has a space that asks you to indicate the 「記入者」(kinyu-sha, or "person filling out the form"), or if there is a designated「家庭から」(katei kara, or "from the family") space in the renrakucho, it is also possible to simply write 「父」(chichi, or "father") or 「母」(haha, or "mother") in place of your name.
The phrases「～にかかりました」 ([name of illness] ni kakarimashita) and「～にかかってしまいました」 ([name of illness] ni kakatte shimaimashita) both mean "I got/contracted (an illness)", and they can be used to mean that you contracted an illness and got over it, or that you contracted an illness and are still sick.
Some names of illnesses that you may encounter are 「中耳炎」 (chuji-en, or "inner ear infection"),「水ぼうそう」(mizuboso, or "chickenpox"),「突発性発疹」(toppatsu-sei hosshin, or "roseola"),「溶連菌（感染症）」(yorenkin [kansen-sho], or "streptococcal infection"),「おたふく（かぜ）」(otafuku [kaze], or "mumps") and「インフルエンザ」(infuruenza, or "influenza"). Some of these illnesses are also commonly encountered in the names of vaccines and so on. There are of course many other illnesses that your child may contract, so if a doctor gives your child a diagnosis of an illness that you are not familiar with, ask the doctor to write down or tell you the name of the illness, and be sure to convey this information to your child's preschool.
「風邪をひきました」(kaze o hikimashita) can mean "My child caught a cold, but now he/she is fine" or "My child caught a cold, and he/she is still sick." As illustrated by the examples, adding information about your child's current condition can help to clarify this point.