This trial is conducted in Europe. The aim of this trial is to investigate safety, tolerability and pharmacokinetic (the exposure of the trial drug in the body) and pharmacodynamic (the effect of the investigated drug on the body) characteristics of insulin degludec (insulin 454) and insulin degludec/insulin aspart (IDegAsp) 50 - formerly SIAM), both explorative formulations, not similar to the proposed commercial formulation, in healthy male Japanese subjects.

Inclusion Criteria:

• Japanese passport holder
• Japanese-born parents
• Body mass index (BMI) between 18.0 and 27.0 kg/m^2 (both inclusive)
• Fasting blood glucose of below or equal to 6 mmol/L
• Healthy male subjects, who are considered to be generally healthy based on an assessment of medical history, physical examination and clinical laboratory data at screening, as assessment of medical history, physical exjudged by the Investigator

Exclusion Criteria:

• The receipt of any investigational drug within 3 months prior to this trial
• Subjects with a history of significant multiple drug allergies or with a known allergy to the trialproduct or any medicine chemically related to the trial product, as judged by the Investigator